mirror of
https://github.com/moparisthebest/SickRage
synced 2024-11-11 03:45:01 -05:00
458 lines
13 KiB
Python
458 lines
13 KiB
Python
# orm/base.py
|
|
# Copyright (C) 2005-2014 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
|
|
|
|
"""Constants and rudimental functions used throughout the ORM.
|
|
|
|
"""
|
|
|
|
from .. import util, inspection, exc as sa_exc
|
|
from ..sql import expression
|
|
from . import exc
|
|
import operator
|
|
|
|
PASSIVE_NO_RESULT = util.symbol('PASSIVE_NO_RESULT',
|
|
"""Symbol returned by a loader callable or other attribute/history
|
|
retrieval operation when a value could not be determined, based
|
|
on loader callable flags.
|
|
"""
|
|
)
|
|
|
|
ATTR_WAS_SET = util.symbol('ATTR_WAS_SET',
|
|
"""Symbol returned by a loader callable to indicate the
|
|
retrieved value, or values, were assigned to their attributes
|
|
on the target object.
|
|
""")
|
|
|
|
ATTR_EMPTY = util.symbol('ATTR_EMPTY',
|
|
"""Symbol used internally to indicate an attribute had no callable.
|
|
""")
|
|
|
|
NO_VALUE = util.symbol('NO_VALUE',
|
|
"""Symbol which may be placed as the 'previous' value of an attribute,
|
|
indicating no value was loaded for an attribute when it was modified,
|
|
and flags indicated we were not to load it.
|
|
"""
|
|
)
|
|
|
|
NEVER_SET = util.symbol('NEVER_SET',
|
|
"""Symbol which may be placed as the 'previous' value of an attribute
|
|
indicating that the attribute had not been assigned to previously.
|
|
"""
|
|
)
|
|
|
|
NO_CHANGE = util.symbol("NO_CHANGE",
|
|
"""No callables or SQL should be emitted on attribute access
|
|
and no state should change""", canonical=0
|
|
)
|
|
|
|
CALLABLES_OK = util.symbol("CALLABLES_OK",
|
|
"""Loader callables can be fired off if a value
|
|
is not present.""", canonical=1
|
|
)
|
|
|
|
SQL_OK = util.symbol("SQL_OK",
|
|
"""Loader callables can emit SQL at least on scalar value
|
|
attributes.""", canonical=2)
|
|
|
|
RELATED_OBJECT_OK = util.symbol("RELATED_OBJECT_OK",
|
|
"""callables can use SQL to load related objects as well
|
|
as scalar value attributes.
|
|
""", canonical=4
|
|
)
|
|
|
|
INIT_OK = util.symbol("INIT_OK",
|
|
"""Attributes should be initialized with a blank
|
|
value (None or an empty collection) upon get, if no other
|
|
value can be obtained.
|
|
""", canonical=8
|
|
)
|
|
|
|
NON_PERSISTENT_OK = util.symbol("NON_PERSISTENT_OK",
|
|
"""callables can be emitted if the parent is not persistent.""",
|
|
canonical=16
|
|
)
|
|
|
|
LOAD_AGAINST_COMMITTED = util.symbol("LOAD_AGAINST_COMMITTED",
|
|
"""callables should use committed values as primary/foreign keys during a load
|
|
""", canonical=32
|
|
)
|
|
|
|
NO_AUTOFLUSH = util.symbol("NO_AUTOFLUSH",
|
|
"""loader callables should disable autoflush.
|
|
""", canonical=64)
|
|
|
|
# pre-packaged sets of flags used as inputs
|
|
PASSIVE_OFF = util.symbol("PASSIVE_OFF",
|
|
"Callables can be emitted in all cases.",
|
|
canonical=(RELATED_OBJECT_OK | NON_PERSISTENT_OK |
|
|
INIT_OK | CALLABLES_OK | SQL_OK)
|
|
)
|
|
PASSIVE_RETURN_NEVER_SET = util.symbol("PASSIVE_RETURN_NEVER_SET",
|
|
"""PASSIVE_OFF ^ INIT_OK""",
|
|
canonical=PASSIVE_OFF ^ INIT_OK
|
|
)
|
|
PASSIVE_NO_INITIALIZE = util.symbol("PASSIVE_NO_INITIALIZE",
|
|
"PASSIVE_RETURN_NEVER_SET ^ CALLABLES_OK",
|
|
canonical=PASSIVE_RETURN_NEVER_SET ^ CALLABLES_OK
|
|
)
|
|
PASSIVE_NO_FETCH = util.symbol("PASSIVE_NO_FETCH",
|
|
"PASSIVE_OFF ^ SQL_OK",
|
|
canonical=PASSIVE_OFF ^ SQL_OK
|
|
)
|
|
PASSIVE_NO_FETCH_RELATED = util.symbol("PASSIVE_NO_FETCH_RELATED",
|
|
"PASSIVE_OFF ^ RELATED_OBJECT_OK",
|
|
canonical=PASSIVE_OFF ^ RELATED_OBJECT_OK
|
|
)
|
|
PASSIVE_ONLY_PERSISTENT = util.symbol("PASSIVE_ONLY_PERSISTENT",
|
|
"PASSIVE_OFF ^ NON_PERSISTENT_OK",
|
|
canonical=PASSIVE_OFF ^ NON_PERSISTENT_OK
|
|
)
|
|
|
|
DEFAULT_MANAGER_ATTR = '_sa_class_manager'
|
|
DEFAULT_STATE_ATTR = '_sa_instance_state'
|
|
_INSTRUMENTOR = ('mapper', 'instrumentor')
|
|
|
|
EXT_CONTINUE = util.symbol('EXT_CONTINUE')
|
|
EXT_STOP = util.symbol('EXT_STOP')
|
|
|
|
ONETOMANY = util.symbol('ONETOMANY',
|
|
"""Indicates the one-to-many direction for a :func:`.relationship`.
|
|
|
|
This symbol is typically used by the internals but may be exposed within
|
|
certain API features.
|
|
|
|
""")
|
|
|
|
MANYTOONE = util.symbol('MANYTOONE',
|
|
"""Indicates the many-to-one direction for a :func:`.relationship`.
|
|
|
|
This symbol is typically used by the internals but may be exposed within
|
|
certain API features.
|
|
|
|
""")
|
|
|
|
MANYTOMANY = util.symbol('MANYTOMANY',
|
|
"""Indicates the many-to-many direction for a :func:`.relationship`.
|
|
|
|
This symbol is typically used by the internals but may be exposed within
|
|
certain API features.
|
|
|
|
""")
|
|
|
|
NOT_EXTENSION = util.symbol('NOT_EXTENSION',
|
|
"""Symbol indicating an :class:`_InspectionAttr` that's
|
|
not part of sqlalchemy.ext.
|
|
|
|
Is assigned to the :attr:`._InspectionAttr.extension_type`
|
|
attibute.
|
|
|
|
""")
|
|
|
|
_none_set = frozenset([None])
|
|
|
|
|
|
def _generative(*assertions):
|
|
"""Mark a method as generative, e.g. method-chained."""
|
|
|
|
@util.decorator
|
|
def generate(fn, *args, **kw):
|
|
self = args[0]._clone()
|
|
for assertion in assertions:
|
|
assertion(self, fn.__name__)
|
|
fn(self, *args[1:], **kw)
|
|
return self
|
|
return generate
|
|
|
|
|
|
# these can be replaced by sqlalchemy.ext.instrumentation
|
|
# if augmented class instrumentation is enabled.
|
|
def manager_of_class(cls):
|
|
return cls.__dict__.get(DEFAULT_MANAGER_ATTR, None)
|
|
|
|
instance_state = operator.attrgetter(DEFAULT_STATE_ATTR)
|
|
|
|
instance_dict = operator.attrgetter('__dict__')
|
|
|
|
def instance_str(instance):
|
|
"""Return a string describing an instance."""
|
|
|
|
return state_str(instance_state(instance))
|
|
|
|
def state_str(state):
|
|
"""Return a string describing an instance via its InstanceState."""
|
|
|
|
if state is None:
|
|
return "None"
|
|
else:
|
|
return '<%s at 0x%x>' % (state.class_.__name__, id(state.obj()))
|
|
|
|
def state_class_str(state):
|
|
"""Return a string describing an instance's class via its InstanceState."""
|
|
|
|
if state is None:
|
|
return "None"
|
|
else:
|
|
return '<%s>' % (state.class_.__name__, )
|
|
|
|
|
|
def attribute_str(instance, attribute):
|
|
return instance_str(instance) + "." + attribute
|
|
|
|
|
|
def state_attribute_str(state, attribute):
|
|
return state_str(state) + "." + attribute
|
|
|
|
def object_mapper(instance):
|
|
"""Given an object, return the primary Mapper associated with the object
|
|
instance.
|
|
|
|
Raises :class:`sqlalchemy.orm.exc.UnmappedInstanceError`
|
|
if no mapping is configured.
|
|
|
|
This function is available via the inspection system as::
|
|
|
|
inspect(instance).mapper
|
|
|
|
Using the inspection system will raise
|
|
:class:`sqlalchemy.exc.NoInspectionAvailable` if the instance is
|
|
not part of a mapping.
|
|
|
|
"""
|
|
return object_state(instance).mapper
|
|
|
|
|
|
def object_state(instance):
|
|
"""Given an object, return the :class:`.InstanceState`
|
|
associated with the object.
|
|
|
|
Raises :class:`sqlalchemy.orm.exc.UnmappedInstanceError`
|
|
if no mapping is configured.
|
|
|
|
Equivalent functionality is available via the :func:`.inspect`
|
|
function as::
|
|
|
|
inspect(instance)
|
|
|
|
Using the inspection system will raise
|
|
:class:`sqlalchemy.exc.NoInspectionAvailable` if the instance is
|
|
not part of a mapping.
|
|
|
|
"""
|
|
state = _inspect_mapped_object(instance)
|
|
if state is None:
|
|
raise exc.UnmappedInstanceError(instance)
|
|
else:
|
|
return state
|
|
|
|
|
|
@inspection._inspects(object)
|
|
def _inspect_mapped_object(instance):
|
|
try:
|
|
return instance_state(instance)
|
|
# TODO: whats the py-2/3 syntax to catch two
|
|
# different kinds of exceptions at once ?
|
|
except exc.UnmappedClassError:
|
|
return None
|
|
except exc.NO_STATE:
|
|
return None
|
|
|
|
|
|
|
|
def _class_to_mapper(class_or_mapper):
|
|
insp = inspection.inspect(class_or_mapper, False)
|
|
if insp is not None:
|
|
return insp.mapper
|
|
else:
|
|
raise exc.UnmappedClassError(class_or_mapper)
|
|
|
|
|
|
def _mapper_or_none(entity):
|
|
"""Return the :class:`.Mapper` for the given class or None if the
|
|
class is not mapped."""
|
|
|
|
insp = inspection.inspect(entity, False)
|
|
if insp is not None:
|
|
return insp.mapper
|
|
else:
|
|
return None
|
|
|
|
|
|
def _is_mapped_class(entity):
|
|
"""Return True if the given object is a mapped class,
|
|
:class:`.Mapper`, or :class:`.AliasedClass`."""
|
|
|
|
insp = inspection.inspect(entity, False)
|
|
return insp is not None and \
|
|
hasattr(insp, "mapper") and \
|
|
(
|
|
insp.is_mapper
|
|
or insp.is_aliased_class
|
|
)
|
|
|
|
def _attr_as_key(attr):
|
|
if hasattr(attr, 'key'):
|
|
return attr.key
|
|
else:
|
|
return expression._column_as_key(attr)
|
|
|
|
|
|
|
|
def _orm_columns(entity):
|
|
insp = inspection.inspect(entity, False)
|
|
if hasattr(insp, 'selectable'):
|
|
return [c for c in insp.selectable.c]
|
|
else:
|
|
return [entity]
|
|
|
|
|
|
|
|
def _is_aliased_class(entity):
|
|
insp = inspection.inspect(entity, False)
|
|
return insp is not None and \
|
|
getattr(insp, "is_aliased_class", False)
|
|
|
|
|
|
def _entity_descriptor(entity, key):
|
|
"""Return a class attribute given an entity and string name.
|
|
|
|
May return :class:`.InstrumentedAttribute` or user-defined
|
|
attribute.
|
|
|
|
"""
|
|
insp = inspection.inspect(entity)
|
|
if insp.is_selectable:
|
|
description = entity
|
|
entity = insp.c
|
|
elif insp.is_aliased_class:
|
|
entity = insp.entity
|
|
description = entity
|
|
elif hasattr(insp, "mapper"):
|
|
description = entity = insp.mapper.class_
|
|
else:
|
|
description = entity
|
|
|
|
try:
|
|
return getattr(entity, key)
|
|
except AttributeError:
|
|
raise sa_exc.InvalidRequestError(
|
|
"Entity '%s' has no property '%s'" %
|
|
(description, key)
|
|
)
|
|
|
|
_state_mapper = util.dottedgetter('manager.mapper')
|
|
|
|
@inspection._inspects(type)
|
|
def _inspect_mapped_class(class_, configure=False):
|
|
try:
|
|
class_manager = manager_of_class(class_)
|
|
if not class_manager.is_mapped:
|
|
return None
|
|
mapper = class_manager.mapper
|
|
if configure and mapper._new_mappers:
|
|
mapper._configure_all()
|
|
return mapper
|
|
|
|
except exc.NO_STATE:
|
|
return None
|
|
|
|
def class_mapper(class_, configure=True):
|
|
"""Given a class, return the primary :class:`.Mapper` associated
|
|
with the key.
|
|
|
|
Raises :exc:`.UnmappedClassError` if no mapping is configured
|
|
on the given class, or :exc:`.ArgumentError` if a non-class
|
|
object is passed.
|
|
|
|
Equivalent functionality is available via the :func:`.inspect`
|
|
function as::
|
|
|
|
inspect(some_mapped_class)
|
|
|
|
Using the inspection system will raise
|
|
:class:`sqlalchemy.exc.NoInspectionAvailable` if the class is not mapped.
|
|
|
|
"""
|
|
mapper = _inspect_mapped_class(class_, configure=configure)
|
|
if mapper is None:
|
|
if not isinstance(class_, type):
|
|
raise sa_exc.ArgumentError(
|
|
"Class object expected, got '%r'." % (class_, ))
|
|
raise exc.UnmappedClassError(class_)
|
|
else:
|
|
return mapper
|
|
|
|
|
|
class _InspectionAttr(object):
|
|
"""A base class applied to all ORM objects that can be returned
|
|
by the :func:`.inspect` function.
|
|
|
|
The attributes defined here allow the usage of simple boolean
|
|
checks to test basic facts about the object returned.
|
|
|
|
While the boolean checks here are basically the same as using
|
|
the Python isinstance() function, the flags here can be used without
|
|
the need to import all of these classes, and also such that
|
|
the SQLAlchemy class system can change while leaving the flags
|
|
here intact for forwards-compatibility.
|
|
|
|
"""
|
|
|
|
is_selectable = False
|
|
"""Return True if this object is an instance of :class:`.Selectable`."""
|
|
|
|
is_aliased_class = False
|
|
"""True if this object is an instance of :class:`.AliasedClass`."""
|
|
|
|
is_instance = False
|
|
"""True if this object is an instance of :class:`.InstanceState`."""
|
|
|
|
is_mapper = False
|
|
"""True if this object is an instance of :class:`.Mapper`."""
|
|
|
|
is_property = False
|
|
"""True if this object is an instance of :class:`.MapperProperty`."""
|
|
|
|
is_attribute = False
|
|
"""True if this object is a Python :term:`descriptor`.
|
|
|
|
This can refer to one of many types. Usually a
|
|
:class:`.QueryableAttribute` which handles attributes events on behalf
|
|
of a :class:`.MapperProperty`. But can also be an extension type
|
|
such as :class:`.AssociationProxy` or :class:`.hybrid_property`.
|
|
The :attr:`._InspectionAttr.extension_type` will refer to a constant
|
|
identifying the specific subtype.
|
|
|
|
.. seealso::
|
|
|
|
:attr:`.Mapper.all_orm_descriptors`
|
|
|
|
"""
|
|
|
|
is_clause_element = False
|
|
"""True if this object is an instance of :class:`.ClauseElement`."""
|
|
|
|
extension_type = NOT_EXTENSION
|
|
"""The extension type, if any.
|
|
Defaults to :data:`.interfaces.NOT_EXTENSION`
|
|
|
|
.. versionadded:: 0.8.0
|
|
|
|
.. seealso::
|
|
|
|
:data:`.HYBRID_METHOD`
|
|
|
|
:data:`.HYBRID_PROPERTY`
|
|
|
|
:data:`.ASSOCIATION_PROXY`
|
|
|
|
"""
|
|
|
|
class _MappedAttribute(object):
|
|
"""Mixin for attributes which should be replaced by mapper-assigned
|
|
attributes.
|
|
|
|
"""
|