mirror of
https://github.com/moparisthebest/SickRage
synced 2024-12-14 20:12:19 -05:00
618 lines
19 KiB
Python
618 lines
19 KiB
Python
# orm/state.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
|
|
|
|
"""Defines instrumentation of instances.
|
|
|
|
This module is usually not directly visible to user applications, but
|
|
defines a large part of the ORM's interactivity.
|
|
|
|
"""
|
|
|
|
import weakref
|
|
from .. import util
|
|
from . import exc as orm_exc, interfaces
|
|
from .path_registry import PathRegistry
|
|
from .base import PASSIVE_NO_RESULT, SQL_OK, NEVER_SET, ATTR_WAS_SET, \
|
|
NO_VALUE, PASSIVE_NO_INITIALIZE, INIT_OK, PASSIVE_OFF
|
|
from . import base
|
|
|
|
class InstanceState(interfaces._InspectionAttr):
|
|
"""tracks state information at the instance level."""
|
|
|
|
session_id = None
|
|
key = None
|
|
runid = None
|
|
load_options = util.EMPTY_SET
|
|
load_path = ()
|
|
insert_order = None
|
|
_strong_obj = None
|
|
modified = False
|
|
expired = False
|
|
deleted = False
|
|
_load_pending = False
|
|
|
|
is_instance = True
|
|
|
|
def __init__(self, obj, manager):
|
|
self.class_ = obj.__class__
|
|
self.manager = manager
|
|
self.obj = weakref.ref(obj, self._cleanup)
|
|
self.callables = {}
|
|
self.committed_state = {}
|
|
|
|
@util.memoized_property
|
|
def attrs(self):
|
|
"""Return a namespace representing each attribute on
|
|
the mapped object, including its current value
|
|
and history.
|
|
|
|
The returned object is an instance of :class:`.AttributeState`.
|
|
|
|
"""
|
|
return util.ImmutableProperties(
|
|
dict(
|
|
(key, AttributeState(self, key))
|
|
for key in self.manager
|
|
)
|
|
)
|
|
|
|
@property
|
|
def transient(self):
|
|
"""Return true if the object is transient."""
|
|
return self.key is None and \
|
|
not self._attached
|
|
|
|
@property
|
|
def pending(self):
|
|
"""Return true if the object is pending."""
|
|
return self.key is None and \
|
|
self._attached
|
|
|
|
@property
|
|
def persistent(self):
|
|
"""Return true if the object is persistent."""
|
|
return self.key is not None and \
|
|
self._attached
|
|
|
|
@property
|
|
def detached(self):
|
|
"""Return true if the object is detached."""
|
|
return self.key is not None and \
|
|
not self._attached
|
|
|
|
@property
|
|
@util.dependencies("sqlalchemy.orm.session")
|
|
def _attached(self, sessionlib):
|
|
return self.session_id is not None and \
|
|
self.session_id in sessionlib._sessions
|
|
|
|
@property
|
|
@util.dependencies("sqlalchemy.orm.session")
|
|
def session(self, sessionlib):
|
|
"""Return the owning :class:`.Session` for this instance,
|
|
or ``None`` if none available."""
|
|
return sessionlib._state_session(self)
|
|
|
|
@property
|
|
def object(self):
|
|
"""Return the mapped object represented by this
|
|
:class:`.InstanceState`."""
|
|
return self.obj()
|
|
|
|
@property
|
|
def identity(self):
|
|
"""Return the mapped identity of the mapped object.
|
|
This is the primary key identity as persisted by the ORM
|
|
which can always be passed directly to
|
|
:meth:`.Query.get`.
|
|
|
|
Returns ``None`` if the object has no primary key identity.
|
|
|
|
.. note::
|
|
An object which is transient or pending
|
|
does **not** have a mapped identity until it is flushed,
|
|
even if its attributes include primary key values.
|
|
|
|
"""
|
|
if self.key is None:
|
|
return None
|
|
else:
|
|
return self.key[1]
|
|
|
|
@property
|
|
def identity_key(self):
|
|
"""Return the identity key for the mapped object.
|
|
|
|
This is the key used to locate the object within
|
|
the :attr:`.Session.identity_map` mapping. It contains
|
|
the identity as returned by :attr:`.identity` within it.
|
|
|
|
|
|
"""
|
|
# TODO: just change .key to .identity_key across
|
|
# the board ? probably
|
|
return self.key
|
|
|
|
@util.memoized_property
|
|
def parents(self):
|
|
return {}
|
|
|
|
@util.memoized_property
|
|
def _pending_mutations(self):
|
|
return {}
|
|
|
|
@util.memoized_property
|
|
def mapper(self):
|
|
"""Return the :class:`.Mapper` used for this mapepd object."""
|
|
return self.manager.mapper
|
|
|
|
@property
|
|
def has_identity(self):
|
|
"""Return ``True`` if this object has an identity key.
|
|
|
|
This should always have the same value as the
|
|
expression ``state.persistent or state.detached``.
|
|
|
|
"""
|
|
return bool(self.key)
|
|
|
|
def _detach(self):
|
|
self.session_id = self._strong_obj = None
|
|
|
|
def _dispose(self):
|
|
self._detach()
|
|
del self.obj
|
|
|
|
def _cleanup(self, ref):
|
|
instance_dict = self._instance_dict()
|
|
if instance_dict:
|
|
instance_dict.discard(self)
|
|
|
|
self.callables = {}
|
|
self.session_id = self._strong_obj = None
|
|
del self.obj
|
|
|
|
def obj(self):
|
|
return None
|
|
|
|
@property
|
|
def dict(self):
|
|
o = self.obj()
|
|
if o is not None:
|
|
return base.instance_dict(o)
|
|
else:
|
|
return {}
|
|
|
|
def _initialize_instance(*mixed, **kwargs):
|
|
self, instance, args = mixed[0], mixed[1], mixed[2:]
|
|
manager = self.manager
|
|
|
|
manager.dispatch.init(self, args, kwargs)
|
|
|
|
try:
|
|
return manager.original_init(*mixed[1:], **kwargs)
|
|
except:
|
|
manager.dispatch.init_failure(self, args, kwargs)
|
|
raise
|
|
|
|
def get_history(self, key, passive):
|
|
return self.manager[key].impl.get_history(self, self.dict, passive)
|
|
|
|
def get_impl(self, key):
|
|
return self.manager[key].impl
|
|
|
|
def _get_pending_mutation(self, key):
|
|
if key not in self._pending_mutations:
|
|
self._pending_mutations[key] = PendingCollection()
|
|
return self._pending_mutations[key]
|
|
|
|
def __getstate__(self):
|
|
state_dict = {'instance': self.obj()}
|
|
state_dict.update(
|
|
(k, self.__dict__[k]) for k in (
|
|
'committed_state', '_pending_mutations', 'modified', 'expired',
|
|
'callables', 'key', 'parents', 'load_options',
|
|
'class_',
|
|
) if k in self.__dict__
|
|
)
|
|
if self.load_path:
|
|
state_dict['load_path'] = self.load_path.serialize()
|
|
|
|
state_dict['manager'] = self.manager._serialize(self, state_dict)
|
|
|
|
return state_dict
|
|
|
|
def __setstate__(self, state_dict):
|
|
inst = state_dict['instance']
|
|
if inst is not None:
|
|
self.obj = weakref.ref(inst, self._cleanup)
|
|
self.class_ = inst.__class__
|
|
else:
|
|
# None being possible here generally new as of 0.7.4
|
|
# due to storage of state in "parents". "class_"
|
|
# also new.
|
|
self.obj = None
|
|
self.class_ = state_dict['class_']
|
|
|
|
self.committed_state = state_dict.get('committed_state', {})
|
|
self._pending_mutations = state_dict.get('_pending_mutations', {})
|
|
self.parents = state_dict.get('parents', {})
|
|
self.modified = state_dict.get('modified', False)
|
|
self.expired = state_dict.get('expired', False)
|
|
self.callables = state_dict.get('callables', {})
|
|
|
|
self.__dict__.update([
|
|
(k, state_dict[k]) for k in (
|
|
'key', 'load_options',
|
|
) if k in state_dict
|
|
])
|
|
|
|
if 'load_path' in state_dict:
|
|
self.load_path = PathRegistry.\
|
|
deserialize(state_dict['load_path'])
|
|
|
|
state_dict['manager'](self, inst, state_dict)
|
|
|
|
def _initialize(self, key):
|
|
"""Set this attribute to an empty value or collection,
|
|
based on the AttributeImpl in use."""
|
|
|
|
self.manager.get_impl(key).initialize(self, self.dict)
|
|
|
|
def _reset(self, dict_, key):
|
|
"""Remove the given attribute and any
|
|
callables associated with it."""
|
|
|
|
old = dict_.pop(key, None)
|
|
if old is not None and self.manager[key].impl.collection:
|
|
self.manager[key].impl._invalidate_collection(old)
|
|
self.callables.pop(key, None)
|
|
|
|
def _expire_attribute_pre_commit(self, dict_, key):
|
|
"""a fast expire that can be called by column loaders during a load.
|
|
|
|
The additional bookkeeping is finished up in commit_all().
|
|
|
|
Should only be called for scalar attributes.
|
|
|
|
This method is actually called a lot with joined-table
|
|
loading, when the second table isn't present in the result.
|
|
|
|
"""
|
|
dict_.pop(key, None)
|
|
self.callables[key] = self
|
|
|
|
@classmethod
|
|
def _row_processor(cls, manager, fn, key):
|
|
impl = manager[key].impl
|
|
if impl.collection:
|
|
def _set_callable(state, dict_, row):
|
|
old = dict_.pop(key, None)
|
|
if old is not None:
|
|
impl._invalidate_collection(old)
|
|
state.callables[key] = fn
|
|
else:
|
|
def _set_callable(state, dict_, row):
|
|
state.callables[key] = fn
|
|
return _set_callable
|
|
|
|
def _expire(self, dict_, modified_set):
|
|
self.expired = True
|
|
if self.modified:
|
|
modified_set.discard(self)
|
|
|
|
self.modified = False
|
|
self._strong_obj = None
|
|
|
|
self.committed_state.clear()
|
|
|
|
InstanceState._pending_mutations._reset(self)
|
|
|
|
# clear out 'parents' collection. not
|
|
# entirely clear how we can best determine
|
|
# which to remove, or not.
|
|
InstanceState.parents._reset(self)
|
|
|
|
for key in self.manager:
|
|
impl = self.manager[key].impl
|
|
if impl.accepts_scalar_loader and \
|
|
(impl.expire_missing or key in dict_):
|
|
self.callables[key] = self
|
|
old = dict_.pop(key, None)
|
|
if impl.collection and old is not None:
|
|
impl._invalidate_collection(old)
|
|
|
|
self.manager.dispatch.expire(self, None)
|
|
|
|
def _expire_attributes(self, dict_, attribute_names):
|
|
pending = self.__dict__.get('_pending_mutations', None)
|
|
|
|
for key in attribute_names:
|
|
impl = self.manager[key].impl
|
|
if impl.accepts_scalar_loader:
|
|
self.callables[key] = self
|
|
old = dict_.pop(key, None)
|
|
if impl.collection and old is not None:
|
|
impl._invalidate_collection(old)
|
|
|
|
self.committed_state.pop(key, None)
|
|
if pending:
|
|
pending.pop(key, None)
|
|
|
|
self.manager.dispatch.expire(self, attribute_names)
|
|
|
|
def __call__(self, state, passive):
|
|
"""__call__ allows the InstanceState to act as a deferred
|
|
callable for loading expired attributes, which is also
|
|
serializable (picklable).
|
|
|
|
"""
|
|
|
|
if not passive & SQL_OK:
|
|
return PASSIVE_NO_RESULT
|
|
|
|
toload = self.expired_attributes.\
|
|
intersection(self.unmodified)
|
|
|
|
self.manager.deferred_scalar_loader(self, toload)
|
|
|
|
# if the loader failed, or this
|
|
# instance state didn't have an identity,
|
|
# the attributes still might be in the callables
|
|
# dict. ensure they are removed.
|
|
for k in toload.intersection(self.callables):
|
|
del self.callables[k]
|
|
|
|
return ATTR_WAS_SET
|
|
|
|
@property
|
|
def unmodified(self):
|
|
"""Return the set of keys which have no uncommitted changes"""
|
|
|
|
return set(self.manager).difference(self.committed_state)
|
|
|
|
def unmodified_intersection(self, keys):
|
|
"""Return self.unmodified.intersection(keys)."""
|
|
|
|
return set(keys).intersection(self.manager).\
|
|
difference(self.committed_state)
|
|
|
|
@property
|
|
def unloaded(self):
|
|
"""Return the set of keys which do not have a loaded value.
|
|
|
|
This includes expired attributes and any other attribute that
|
|
was never populated or modified.
|
|
|
|
"""
|
|
return set(self.manager).\
|
|
difference(self.committed_state).\
|
|
difference(self.dict)
|
|
|
|
@property
|
|
def _unloaded_non_object(self):
|
|
return self.unloaded.intersection(
|
|
attr for attr in self.manager
|
|
if self.manager[attr].impl.accepts_scalar_loader
|
|
)
|
|
|
|
@property
|
|
def expired_attributes(self):
|
|
"""Return the set of keys which are 'expired' to be loaded by
|
|
the manager's deferred scalar loader, assuming no pending
|
|
changes.
|
|
|
|
see also the ``unmodified`` collection which is intersected
|
|
against this set when a refresh operation occurs.
|
|
|
|
"""
|
|
return set([k for k, v in self.callables.items() if v is self])
|
|
|
|
def _instance_dict(self):
|
|
return None
|
|
|
|
def _modified_event(self, dict_, attr, previous, collection=False, force=False):
|
|
if not attr.send_modified_events:
|
|
return
|
|
if attr.key not in self.committed_state or force:
|
|
if collection:
|
|
if previous is NEVER_SET:
|
|
if attr.key in dict_:
|
|
previous = dict_[attr.key]
|
|
|
|
if previous not in (None, NO_VALUE, NEVER_SET):
|
|
previous = attr.copy(previous)
|
|
|
|
self.committed_state[attr.key] = previous
|
|
|
|
# assert self._strong_obj is None or self.modified
|
|
|
|
if (self.session_id and self._strong_obj is None) \
|
|
or not self.modified:
|
|
instance_dict = self._instance_dict()
|
|
if instance_dict:
|
|
instance_dict._modified.add(self)
|
|
|
|
# only create _strong_obj link if attached
|
|
# to a session
|
|
|
|
inst = self.obj()
|
|
if self.session_id:
|
|
self._strong_obj = inst
|
|
|
|
if inst is None:
|
|
raise orm_exc.ObjectDereferencedError(
|
|
"Can't emit change event for attribute '%s' - "
|
|
"parent object of type %s has been garbage "
|
|
"collected."
|
|
% (
|
|
self.manager[attr.key],
|
|
base.state_class_str(self)
|
|
))
|
|
self.modified = True
|
|
|
|
def _commit(self, dict_, keys):
|
|
"""Commit attributes.
|
|
|
|
This is used by a partial-attribute load operation to mark committed
|
|
those attributes which were refreshed from the database.
|
|
|
|
Attributes marked as "expired" can potentially remain "expired" after
|
|
this step if a value was not populated in state.dict.
|
|
|
|
"""
|
|
for key in keys:
|
|
self.committed_state.pop(key, None)
|
|
|
|
self.expired = False
|
|
|
|
for key in set(self.callables).\
|
|
intersection(keys).\
|
|
intersection(dict_):
|
|
del self.callables[key]
|
|
|
|
def _commit_all(self, dict_, instance_dict=None):
|
|
"""commit all attributes unconditionally.
|
|
|
|
This is used after a flush() or a full load/refresh
|
|
to remove all pending state from the instance.
|
|
|
|
- all attributes are marked as "committed"
|
|
- the "strong dirty reference" is removed
|
|
- the "modified" flag is set to False
|
|
- any "expired" markers/callables for attributes loaded are removed.
|
|
|
|
Attributes marked as "expired" can potentially remain
|
|
"expired" after this step if a value was not populated in state.dict.
|
|
|
|
"""
|
|
self._commit_all_states([(self, dict_)], instance_dict)
|
|
|
|
@classmethod
|
|
def _commit_all_states(self, iter, instance_dict=None):
|
|
"""Mass version of commit_all()."""
|
|
|
|
for state, dict_ in iter:
|
|
state.committed_state.clear()
|
|
InstanceState._pending_mutations._reset(state)
|
|
|
|
callables = state.callables
|
|
for key in list(callables):
|
|
if key in dict_ and callables[key] is state:
|
|
del callables[key]
|
|
|
|
if instance_dict and state.modified:
|
|
instance_dict._modified.discard(state)
|
|
|
|
state.modified = state.expired = False
|
|
state._strong_obj = None
|
|
|
|
|
|
class AttributeState(object):
|
|
"""Provide an inspection interface corresponding
|
|
to a particular attribute on a particular mapped object.
|
|
|
|
The :class:`.AttributeState` object is accessed
|
|
via the :attr:`.InstanceState.attrs` collection
|
|
of a particular :class:`.InstanceState`::
|
|
|
|
from sqlalchemy import inspect
|
|
|
|
insp = inspect(some_mapped_object)
|
|
attr_state = insp.attrs.some_attribute
|
|
|
|
"""
|
|
|
|
def __init__(self, state, key):
|
|
self.state = state
|
|
self.key = key
|
|
|
|
@property
|
|
def loaded_value(self):
|
|
"""The current value of this attribute as loaded from the database.
|
|
|
|
If the value has not been loaded, or is otherwise not present
|
|
in the object's dictionary, returns NO_VALUE.
|
|
|
|
"""
|
|
return self.state.dict.get(self.key, NO_VALUE)
|
|
|
|
@property
|
|
def value(self):
|
|
"""Return the value of this attribute.
|
|
|
|
This operation is equivalent to accessing the object's
|
|
attribute directly or via ``getattr()``, and will fire
|
|
off any pending loader callables if needed.
|
|
|
|
"""
|
|
return self.state.manager[self.key].__get__(
|
|
self.state.obj(), self.state.class_)
|
|
|
|
@property
|
|
def history(self):
|
|
"""Return the current pre-flush change history for
|
|
this attribute, via the :class:`.History` interface.
|
|
|
|
This method will **not** emit loader callables if the value of the
|
|
attribute is unloaded.
|
|
|
|
.. seealso::
|
|
|
|
:meth:`.AttributeState.load_history` - retrieve history
|
|
using loader callables if the value is not locally present.
|
|
|
|
:func:`.attributes.get_history` - underlying function
|
|
|
|
"""
|
|
return self.state.get_history(self.key,
|
|
PASSIVE_NO_INITIALIZE)
|
|
|
|
def load_history(self):
|
|
"""Return the current pre-flush change history for
|
|
this attribute, via the :class:`.History` interface.
|
|
|
|
This method **will** emit loader callables if the value of the
|
|
attribute is unloaded.
|
|
|
|
.. seealso::
|
|
|
|
:attr:`.AttributeState.history`
|
|
|
|
:func:`.attributes.get_history` - underlying function
|
|
|
|
.. versionadded:: 0.9.0
|
|
|
|
"""
|
|
return self.state.get_history(self.key,
|
|
PASSIVE_OFF ^ INIT_OK)
|
|
|
|
|
|
|
|
class PendingCollection(object):
|
|
"""A writable placeholder for an unloaded collection.
|
|
|
|
Stores items appended to and removed from a collection that has not yet
|
|
been loaded. When the collection is loaded, the changes stored in
|
|
PendingCollection are applied to it to produce the final result.
|
|
|
|
"""
|
|
def __init__(self):
|
|
self.deleted_items = util.IdentitySet()
|
|
self.added_items = util.OrderedIdentitySet()
|
|
|
|
def append(self, value):
|
|
if value in self.deleted_items:
|
|
self.deleted_items.remove(value)
|
|
else:
|
|
self.added_items.add(value)
|
|
|
|
def remove(self, value):
|
|
if value in self.added_items:
|
|
self.added_items.remove(value)
|
|
else:
|
|
self.deleted_items.add(value)
|