mirror of
https://github.com/JonathanHerrewijnen/calibre-web.git
synced 2024-11-14 23:20:24 +00:00
479 lines
16 KiB
Python
479 lines
16 KiB
Python
# orm/descriptor_props.py
|
|
# Copyright (C) 2005-2013 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
|
|
|
|
"""Descriptor properties are more "auxiliary" properties
|
|
that exist as configurational elements, but don't participate
|
|
as actively in the load/persist ORM loop.
|
|
|
|
"""
|
|
|
|
from .interfaces import MapperProperty, PropComparator
|
|
from .util import _none_set
|
|
from . import attributes, strategies
|
|
from .. import util, sql, exc as sa_exc, event, schema
|
|
from ..sql import expression
|
|
properties = util.importlater('sqlalchemy.orm', 'properties')
|
|
|
|
|
|
class DescriptorProperty(MapperProperty):
|
|
""":class:`.MapperProperty` which proxies access to a
|
|
user-defined descriptor."""
|
|
|
|
doc = None
|
|
|
|
def instrument_class(self, mapper):
|
|
prop = self
|
|
|
|
class _ProxyImpl(object):
|
|
accepts_scalar_loader = False
|
|
expire_missing = True
|
|
collection = False
|
|
|
|
def __init__(self, key):
|
|
self.key = key
|
|
|
|
if hasattr(prop, 'get_history'):
|
|
def get_history(self, state, dict_,
|
|
passive=attributes.PASSIVE_OFF):
|
|
return prop.get_history(state, dict_, passive)
|
|
|
|
if self.descriptor is None:
|
|
desc = getattr(mapper.class_, self.key, None)
|
|
if mapper._is_userland_descriptor(desc):
|
|
self.descriptor = desc
|
|
|
|
if self.descriptor is None:
|
|
def fset(obj, value):
|
|
setattr(obj, self.name, value)
|
|
|
|
def fdel(obj):
|
|
delattr(obj, self.name)
|
|
|
|
def fget(obj):
|
|
return getattr(obj, self.name)
|
|
|
|
self.descriptor = property(
|
|
fget=fget,
|
|
fset=fset,
|
|
fdel=fdel,
|
|
)
|
|
|
|
proxy_attr = attributes.\
|
|
create_proxied_attribute(self.descriptor)\
|
|
(
|
|
self.parent.class_,
|
|
self.key,
|
|
self.descriptor,
|
|
lambda: self._comparator_factory(mapper),
|
|
doc=self.doc,
|
|
original_property=self
|
|
)
|
|
proxy_attr.impl = _ProxyImpl(self.key)
|
|
mapper.class_manager.instrument_attribute(self.key, proxy_attr)
|
|
|
|
|
|
class CompositeProperty(DescriptorProperty):
|
|
"""Defines a "composite" mapped attribute, representing a collection
|
|
of columns as one attribute.
|
|
|
|
:class:`.CompositeProperty` is constructed using the :func:`.composite`
|
|
function.
|
|
|
|
See also:
|
|
|
|
:ref:`mapper_composite`
|
|
|
|
"""
|
|
def __init__(self, class_, *attrs, **kwargs):
|
|
self.attrs = attrs
|
|
self.composite_class = class_
|
|
self.active_history = kwargs.get('active_history', False)
|
|
self.deferred = kwargs.get('deferred', False)
|
|
self.group = kwargs.get('group', None)
|
|
self.comparator_factory = kwargs.pop('comparator_factory',
|
|
self.__class__.Comparator)
|
|
if 'info' in kwargs:
|
|
self.info = kwargs.pop('info')
|
|
|
|
util.set_creation_order(self)
|
|
self._create_descriptor()
|
|
|
|
def instrument_class(self, mapper):
|
|
super(CompositeProperty, self).instrument_class(mapper)
|
|
self._setup_event_handlers()
|
|
|
|
def do_init(self):
|
|
"""Initialization which occurs after the :class:`.CompositeProperty`
|
|
has been associated with its parent mapper.
|
|
|
|
"""
|
|
self._init_props()
|
|
self._setup_arguments_on_columns()
|
|
|
|
def _create_descriptor(self):
|
|
"""Create the Python descriptor that will serve as
|
|
the access point on instances of the mapped class.
|
|
|
|
"""
|
|
|
|
def fget(instance):
|
|
dict_ = attributes.instance_dict(instance)
|
|
state = attributes.instance_state(instance)
|
|
|
|
if self.key not in dict_:
|
|
# key not present. Iterate through related
|
|
# attributes, retrieve their values. This
|
|
# ensures they all load.
|
|
values = [
|
|
getattr(instance, key)
|
|
for key in self._attribute_keys
|
|
]
|
|
|
|
# current expected behavior here is that the composite is
|
|
# created on access if the object is persistent or if
|
|
# col attributes have non-None. This would be better
|
|
# if the composite were created unconditionally,
|
|
# but that would be a behavioral change.
|
|
if self.key not in dict_ and (
|
|
state.key is not None or
|
|
not _none_set.issuperset(values)
|
|
):
|
|
dict_[self.key] = self.composite_class(*values)
|
|
state.manager.dispatch.refresh(state, None, [self.key])
|
|
|
|
return dict_.get(self.key, None)
|
|
|
|
def fset(instance, value):
|
|
dict_ = attributes.instance_dict(instance)
|
|
state = attributes.instance_state(instance)
|
|
attr = state.manager[self.key]
|
|
previous = dict_.get(self.key, attributes.NO_VALUE)
|
|
for fn in attr.dispatch.set:
|
|
value = fn(state, value, previous, attr.impl)
|
|
dict_[self.key] = value
|
|
if value is None:
|
|
for key in self._attribute_keys:
|
|
setattr(instance, key, None)
|
|
else:
|
|
for key, value in zip(
|
|
self._attribute_keys,
|
|
value.__composite_values__()):
|
|
setattr(instance, key, value)
|
|
|
|
def fdel(instance):
|
|
state = attributes.instance_state(instance)
|
|
dict_ = attributes.instance_dict(instance)
|
|
previous = dict_.pop(self.key, attributes.NO_VALUE)
|
|
attr = state.manager[self.key]
|
|
attr.dispatch.remove(state, previous, attr.impl)
|
|
for key in self._attribute_keys:
|
|
setattr(instance, key, None)
|
|
|
|
self.descriptor = property(fget, fset, fdel)
|
|
|
|
@util.memoized_property
|
|
def _comparable_elements(self):
|
|
return [
|
|
getattr(self.parent.class_, prop.key)
|
|
for prop in self.props
|
|
]
|
|
|
|
def _init_props(self):
|
|
self.props = props = []
|
|
for attr in self.attrs:
|
|
if isinstance(attr, basestring):
|
|
prop = self.parent.get_property(attr)
|
|
elif isinstance(attr, schema.Column):
|
|
prop = self.parent._columntoproperty[attr]
|
|
elif isinstance(attr, attributes.InstrumentedAttribute):
|
|
prop = attr.property
|
|
props.append(prop)
|
|
|
|
@property
|
|
def columns(self):
|
|
return [a for a in self.attrs if isinstance(a, schema.Column)]
|
|
|
|
def _setup_arguments_on_columns(self):
|
|
"""Propagate configuration arguments made on this composite
|
|
to the target columns, for those that apply.
|
|
|
|
"""
|
|
for prop in self.props:
|
|
prop.active_history = self.active_history
|
|
if self.deferred:
|
|
prop.deferred = self.deferred
|
|
prop.strategy_class = strategies.DeferredColumnLoader
|
|
prop.group = self.group
|
|
|
|
def _setup_event_handlers(self):
|
|
"""Establish events that populate/expire the composite attribute."""
|
|
|
|
def load_handler(state, *args):
|
|
dict_ = state.dict
|
|
|
|
if self.key in dict_:
|
|
return
|
|
|
|
# if column elements aren't loaded, skip.
|
|
# __get__() will initiate a load for those
|
|
# columns
|
|
for k in self._attribute_keys:
|
|
if k not in dict_:
|
|
return
|
|
|
|
#assert self.key not in dict_
|
|
dict_[self.key] = self.composite_class(
|
|
*[state.dict[key] for key in
|
|
self._attribute_keys]
|
|
)
|
|
|
|
def expire_handler(state, keys):
|
|
if keys is None or set(self._attribute_keys).intersection(keys):
|
|
state.dict.pop(self.key, None)
|
|
|
|
def insert_update_handler(mapper, connection, state):
|
|
"""After an insert or update, some columns may be expired due
|
|
to server side defaults, or re-populated due to client side
|
|
defaults. Pop out the composite value here so that it
|
|
recreates.
|
|
|
|
"""
|
|
|
|
state.dict.pop(self.key, None)
|
|
|
|
event.listen(self.parent, 'after_insert',
|
|
insert_update_handler, raw=True)
|
|
event.listen(self.parent, 'after_update',
|
|
insert_update_handler, raw=True)
|
|
event.listen(self.parent, 'load',
|
|
load_handler, raw=True, propagate=True)
|
|
event.listen(self.parent, 'refresh',
|
|
load_handler, raw=True, propagate=True)
|
|
event.listen(self.parent, 'expire',
|
|
expire_handler, raw=True, propagate=True)
|
|
|
|
# TODO: need a deserialize hook here
|
|
|
|
@util.memoized_property
|
|
def _attribute_keys(self):
|
|
return [
|
|
prop.key for prop in self.props
|
|
]
|
|
|
|
def get_history(self, state, dict_, passive=attributes.PASSIVE_OFF):
|
|
"""Provided for userland code that uses attributes.get_history()."""
|
|
|
|
added = []
|
|
deleted = []
|
|
|
|
has_history = False
|
|
for prop in self.props:
|
|
key = prop.key
|
|
hist = state.manager[key].impl.get_history(state, dict_)
|
|
if hist.has_changes():
|
|
has_history = True
|
|
|
|
non_deleted = hist.non_deleted()
|
|
if non_deleted:
|
|
added.extend(non_deleted)
|
|
else:
|
|
added.append(None)
|
|
if hist.deleted:
|
|
deleted.extend(hist.deleted)
|
|
else:
|
|
deleted.append(None)
|
|
|
|
if has_history:
|
|
return attributes.History(
|
|
[self.composite_class(*added)],
|
|
(),
|
|
[self.composite_class(*deleted)]
|
|
)
|
|
else:
|
|
return attributes.History(
|
|
(), [self.composite_class(*added)], ()
|
|
)
|
|
|
|
def _comparator_factory(self, mapper):
|
|
return self.comparator_factory(self, mapper)
|
|
|
|
class Comparator(PropComparator):
|
|
"""Produce boolean, comparison, and other operators for
|
|
:class:`.CompositeProperty` attributes.
|
|
|
|
See the example in :ref:`composite_operations` for an overview
|
|
of usage , as well as the documentation for :class:`.PropComparator`.
|
|
|
|
See also:
|
|
|
|
:class:`.PropComparator`
|
|
|
|
:class:`.ColumnOperators`
|
|
|
|
:ref:`types_operators`
|
|
|
|
:attr:`.TypeEngine.comparator_factory`
|
|
|
|
"""
|
|
|
|
def __clause_element__(self):
|
|
return expression.ClauseList(group=False, *self._comparable_elements)
|
|
|
|
__hash__ = None
|
|
|
|
@util.memoized_property
|
|
def _comparable_elements(self):
|
|
if self.adapter:
|
|
# we need to do a little fudging here because
|
|
# the adapter function we're given only accepts
|
|
# ColumnElements, but our prop._comparable_elements is returning
|
|
# InstrumentedAttribute, because we support the use case
|
|
# of composites that refer to relationships. The better
|
|
# solution here is to open up how AliasedClass interacts
|
|
# with PropComparators so more context is available.
|
|
return [self.adapter(x.__clause_element__())
|
|
for x in self.prop._comparable_elements]
|
|
else:
|
|
return self.prop._comparable_elements
|
|
|
|
def __eq__(self, other):
|
|
if other is None:
|
|
values = [None] * len(self.prop._comparable_elements)
|
|
else:
|
|
values = other.__composite_values__()
|
|
comparisons = [
|
|
a == b
|
|
for a, b in zip(self.prop._comparable_elements, values)
|
|
]
|
|
if self.adapter:
|
|
comparisons = [self.adapter(x) for x in comparisons]
|
|
return sql.and_(*comparisons)
|
|
|
|
def __ne__(self, other):
|
|
return sql.not_(self.__eq__(other))
|
|
|
|
def __str__(self):
|
|
return str(self.parent.class_.__name__) + "." + self.key
|
|
|
|
|
|
class ConcreteInheritedProperty(DescriptorProperty):
|
|
"""A 'do nothing' :class:`.MapperProperty` that disables
|
|
an attribute on a concrete subclass that is only present
|
|
on the inherited mapper, not the concrete classes' mapper.
|
|
|
|
Cases where this occurs include:
|
|
|
|
* When the superclass mapper is mapped against a
|
|
"polymorphic union", which includes all attributes from
|
|
all subclasses.
|
|
* When a relationship() is configured on an inherited mapper,
|
|
but not on the subclass mapper. Concrete mappers require
|
|
that relationship() is configured explicitly on each
|
|
subclass.
|
|
|
|
"""
|
|
|
|
def _comparator_factory(self, mapper):
|
|
comparator_callable = None
|
|
|
|
for m in self.parent.iterate_to_root():
|
|
p = m._props[self.key]
|
|
if not isinstance(p, ConcreteInheritedProperty):
|
|
comparator_callable = p.comparator_factory
|
|
break
|
|
return comparator_callable
|
|
|
|
def __init__(self):
|
|
def warn():
|
|
raise AttributeError("Concrete %s does not implement "
|
|
"attribute %r at the instance level. Add this "
|
|
"property explicitly to %s." %
|
|
(self.parent, self.key, self.parent))
|
|
|
|
class NoninheritedConcreteProp(object):
|
|
def __set__(s, obj, value):
|
|
warn()
|
|
|
|
def __delete__(s, obj):
|
|
warn()
|
|
|
|
def __get__(s, obj, owner):
|
|
if obj is None:
|
|
return self.descriptor
|
|
warn()
|
|
self.descriptor = NoninheritedConcreteProp()
|
|
|
|
|
|
class SynonymProperty(DescriptorProperty):
|
|
|
|
def __init__(self, name, map_column=None,
|
|
descriptor=None, comparator_factory=None,
|
|
doc=None):
|
|
self.name = name
|
|
self.map_column = map_column
|
|
self.descriptor = descriptor
|
|
self.comparator_factory = comparator_factory
|
|
self.doc = doc or (descriptor and descriptor.__doc__) or None
|
|
|
|
util.set_creation_order(self)
|
|
|
|
# TODO: when initialized, check _proxied_property,
|
|
# emit a warning if its not a column-based property
|
|
|
|
@util.memoized_property
|
|
def _proxied_property(self):
|
|
return getattr(self.parent.class_, self.name).property
|
|
|
|
def _comparator_factory(self, mapper):
|
|
prop = self._proxied_property
|
|
|
|
if self.comparator_factory:
|
|
comp = self.comparator_factory(prop, mapper)
|
|
else:
|
|
comp = prop.comparator_factory(prop, mapper)
|
|
return comp
|
|
|
|
def set_parent(self, parent, init):
|
|
if self.map_column:
|
|
# implement the 'map_column' option.
|
|
if self.key not in parent.mapped_table.c:
|
|
raise sa_exc.ArgumentError(
|
|
"Can't compile synonym '%s': no column on table "
|
|
"'%s' named '%s'"
|
|
% (self.name, parent.mapped_table.description, self.key))
|
|
elif parent.mapped_table.c[self.key] in \
|
|
parent._columntoproperty and \
|
|
parent._columntoproperty[
|
|
parent.mapped_table.c[self.key]
|
|
].key == self.name:
|
|
raise sa_exc.ArgumentError(
|
|
"Can't call map_column=True for synonym %r=%r, "
|
|
"a ColumnProperty already exists keyed to the name "
|
|
"%r for column %r" %
|
|
(self.key, self.name, self.name, self.key)
|
|
)
|
|
p = properties.ColumnProperty(parent.mapped_table.c[self.key])
|
|
parent._configure_property(
|
|
self.name, p,
|
|
init=init,
|
|
setparent=True)
|
|
p._mapped_by_synonym = self.key
|
|
|
|
self.parent = parent
|
|
|
|
|
|
class ComparableProperty(DescriptorProperty):
|
|
"""Instruments a Python property for use in query expressions."""
|
|
|
|
def __init__(self, comparator_factory, descriptor=None, doc=None):
|
|
self.descriptor = descriptor
|
|
self.comparator_factory = comparator_factory
|
|
self.doc = doc or (descriptor and descriptor.__doc__) or None
|
|
util.set_creation_order(self)
|
|
|
|
def _comparator_factory(self, mapper):
|
|
return self.comparator_factory(self, mapper)
|