356 lines
10 KiB
Python
356 lines
10 KiB
Python
# orm/identity.py
|
|
# Copyright (C) 2005-2018 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
|
|
|
|
import weakref
|
|
from . import attributes
|
|
from .. import util
|
|
from .. import exc as sa_exc
|
|
from . import util as orm_util
|
|
|
|
class IdentityMap(object):
|
|
def __init__(self):
|
|
self._dict = {}
|
|
self._modified = set()
|
|
self._wr = weakref.ref(self)
|
|
|
|
def keys(self):
|
|
return self._dict.keys()
|
|
|
|
def replace(self, state):
|
|
raise NotImplementedError()
|
|
|
|
def add(self, state):
|
|
raise NotImplementedError()
|
|
|
|
def _add_unpresent(self, state, key):
|
|
"""optional inlined form of add() which can assume item isn't present
|
|
in the map"""
|
|
self.add(state)
|
|
|
|
def update(self, dict):
|
|
raise NotImplementedError("IdentityMap uses add() to insert data")
|
|
|
|
def clear(self):
|
|
raise NotImplementedError("IdentityMap uses remove() to remove data")
|
|
|
|
def _manage_incoming_state(self, state):
|
|
state._instance_dict = self._wr
|
|
|
|
if state.modified:
|
|
self._modified.add(state)
|
|
|
|
def _manage_removed_state(self, state):
|
|
del state._instance_dict
|
|
if state.modified:
|
|
self._modified.discard(state)
|
|
|
|
def _dirty_states(self):
|
|
return self._modified
|
|
|
|
def check_modified(self):
|
|
"""return True if any InstanceStates present have been marked
|
|
as 'modified'.
|
|
|
|
"""
|
|
return bool(self._modified)
|
|
|
|
def has_key(self, key):
|
|
return key in self
|
|
|
|
def popitem(self):
|
|
raise NotImplementedError("IdentityMap uses remove() to remove data")
|
|
|
|
def pop(self, key, *args):
|
|
raise NotImplementedError("IdentityMap uses remove() to remove data")
|
|
|
|
def setdefault(self, key, default=None):
|
|
raise NotImplementedError("IdentityMap uses add() to insert data")
|
|
|
|
def __len__(self):
|
|
return len(self._dict)
|
|
|
|
def copy(self):
|
|
raise NotImplementedError()
|
|
|
|
def __setitem__(self, key, value):
|
|
raise NotImplementedError("IdentityMap uses add() to insert data")
|
|
|
|
def __delitem__(self, key):
|
|
raise NotImplementedError("IdentityMap uses remove() to remove data")
|
|
|
|
|
|
class WeakInstanceDict(IdentityMap):
|
|
|
|
def __getitem__(self, key):
|
|
state = self._dict[key]
|
|
o = state.obj()
|
|
if o is None:
|
|
raise KeyError(key)
|
|
return o
|
|
|
|
def __contains__(self, key):
|
|
try:
|
|
if key in self._dict:
|
|
state = self._dict[key]
|
|
o = state.obj()
|
|
else:
|
|
return False
|
|
except KeyError:
|
|
return False
|
|
else:
|
|
return o is not None
|
|
|
|
def contains_state(self, state):
|
|
if state.key in self._dict:
|
|
try:
|
|
return self._dict[state.key] is state
|
|
except KeyError:
|
|
return False
|
|
else:
|
|
return False
|
|
|
|
def replace(self, state):
|
|
if state.key in self._dict:
|
|
try:
|
|
existing = self._dict[state.key]
|
|
except KeyError:
|
|
# catch gc removed the key after we just checked for it
|
|
pass
|
|
else:
|
|
if existing is not state:
|
|
self._manage_removed_state(existing)
|
|
else:
|
|
return
|
|
|
|
self._dict[state.key] = state
|
|
self._manage_incoming_state(state)
|
|
|
|
def add(self, state):
|
|
key = state.key
|
|
# inline of self.__contains__
|
|
if key in self._dict:
|
|
try:
|
|
existing_state = self._dict[key]
|
|
except KeyError:
|
|
# catch gc removed the key after we just checked for it
|
|
pass
|
|
else:
|
|
if existing_state is not state:
|
|
o = existing_state.obj()
|
|
if o is not None:
|
|
raise sa_exc.InvalidRequestError(
|
|
"Can't attach instance "
|
|
"%s; another instance with key %s is already "
|
|
"present in this session." % (
|
|
orm_util.state_str(state), state.key))
|
|
else:
|
|
return False
|
|
self._dict[key] = state
|
|
self._manage_incoming_state(state)
|
|
return True
|
|
|
|
def _add_unpresent(self, state, key):
|
|
# inlined form of add() called by loading.py
|
|
self._dict[key] = state
|
|
state._instance_dict = self._wr
|
|
|
|
def get(self, key, default=None):
|
|
if key not in self._dict:
|
|
return default
|
|
try:
|
|
state = self._dict[key]
|
|
except KeyError:
|
|
# catch gc removed the key after we just checked for it
|
|
return default
|
|
else:
|
|
o = state.obj()
|
|
if o is None:
|
|
return default
|
|
return o
|
|
|
|
def items(self):
|
|
values = self.all_states()
|
|
result = []
|
|
for state in values:
|
|
value = state.obj()
|
|
if value is not None:
|
|
result.append((state.key, value))
|
|
return result
|
|
|
|
def values(self):
|
|
values = self.all_states()
|
|
result = []
|
|
for state in values:
|
|
value = state.obj()
|
|
if value is not None:
|
|
result.append(value)
|
|
|
|
return result
|
|
|
|
def __iter__(self):
|
|
return iter(self.keys())
|
|
|
|
if util.py2k:
|
|
|
|
def iteritems(self):
|
|
return iter(self.items())
|
|
|
|
def itervalues(self):
|
|
return iter(self.values())
|
|
|
|
def all_states(self):
|
|
if util.py2k:
|
|
return self._dict.values()
|
|
else:
|
|
return list(self._dict.values())
|
|
|
|
def _fast_discard(self, state):
|
|
# used by InstanceState for state being
|
|
# GC'ed, inlines _managed_removed_state
|
|
try:
|
|
st = self._dict[state.key]
|
|
except KeyError:
|
|
# catch gc removed the key after we just checked for it
|
|
pass
|
|
else:
|
|
if st is state:
|
|
self._dict.pop(state.key, None)
|
|
|
|
def discard(self, state):
|
|
self.safe_discard(state)
|
|
|
|
def safe_discard(self, state):
|
|
if state.key in self._dict:
|
|
try:
|
|
st = self._dict[state.key]
|
|
except KeyError:
|
|
# catch gc removed the key after we just checked for it
|
|
pass
|
|
else:
|
|
if st is state:
|
|
self._dict.pop(state.key, None)
|
|
self._manage_removed_state(state)
|
|
|
|
def prune(self):
|
|
return 0
|
|
|
|
|
|
class StrongInstanceDict(IdentityMap):
|
|
"""A 'strong-referencing' version of the identity map.
|
|
|
|
.. deprecated 1.1::
|
|
The strong
|
|
reference identity map is legacy. See the
|
|
recipe at :ref:`session_referencing_behavior` for
|
|
an event-based approach to maintaining strong identity
|
|
references.
|
|
|
|
|
|
"""
|
|
|
|
if util.py2k:
|
|
def itervalues(self):
|
|
return self._dict.itervalues()
|
|
|
|
def iteritems(self):
|
|
return self._dict.iteritems()
|
|
|
|
def __iter__(self):
|
|
return iter(self.dict_)
|
|
|
|
def __getitem__(self, key):
|
|
return self._dict[key]
|
|
|
|
def __contains__(self, key):
|
|
return key in self._dict
|
|
|
|
def get(self, key, default=None):
|
|
return self._dict.get(key, default)
|
|
|
|
def values(self):
|
|
return self._dict.values()
|
|
|
|
def items(self):
|
|
return self._dict.items()
|
|
|
|
def all_states(self):
|
|
return [attributes.instance_state(o) for o in self.values()]
|
|
|
|
def contains_state(self, state):
|
|
return (
|
|
state.key in self and
|
|
attributes.instance_state(self[state.key]) is state)
|
|
|
|
def replace(self, state):
|
|
if state.key in self._dict:
|
|
existing = self._dict[state.key]
|
|
existing = attributes.instance_state(existing)
|
|
if existing is not state:
|
|
self._manage_removed_state(existing)
|
|
else:
|
|
return
|
|
|
|
self._dict[state.key] = state.obj()
|
|
self._manage_incoming_state(state)
|
|
|
|
def add(self, state):
|
|
if state.key in self:
|
|
if attributes.instance_state(self._dict[state.key]) is not state:
|
|
raise sa_exc.InvalidRequestError(
|
|
"Can't attach instance "
|
|
"%s; another instance with key %s is already "
|
|
"present in this session." % (
|
|
orm_util.state_str(state), state.key))
|
|
return False
|
|
else:
|
|
self._dict[state.key] = state.obj()
|
|
self._manage_incoming_state(state)
|
|
return True
|
|
|
|
def _add_unpresent(self, state, key):
|
|
# inlined form of add() called by loading.py
|
|
self._dict[key] = state.obj()
|
|
state._instance_dict = self._wr
|
|
|
|
def _fast_discard(self, state):
|
|
# used by InstanceState for state being
|
|
# GC'ed, inlines _managed_removed_state
|
|
try:
|
|
obj = self._dict[state.key]
|
|
except KeyError:
|
|
# catch gc removed the key after we just checked for it
|
|
pass
|
|
else:
|
|
if attributes.instance_state(obj) is state:
|
|
self._dict.pop(state.key, None)
|
|
|
|
def discard(self, state):
|
|
self.safe_discard(state)
|
|
|
|
def safe_discard(self, state):
|
|
if state.key in self._dict:
|
|
obj = self._dict[state.key]
|
|
st = attributes.instance_state(obj)
|
|
if st is state:
|
|
self._dict.pop(state.key, None)
|
|
self._manage_removed_state(state)
|
|
|
|
def prune(self):
|
|
"""prune unreferenced, non-dirty states."""
|
|
|
|
ref_count = len(self)
|
|
dirty = [s.obj() for s in self.all_states() if s.modified]
|
|
|
|
# work around http://bugs.python.org/issue6149
|
|
keepers = weakref.WeakValueDictionary()
|
|
keepers.update(self)
|
|
|
|
self._dict.clear()
|
|
self._dict.update(keepers)
|
|
self.modified = bool(dirty)
|
|
return ref_count - len(self)
|