You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
442 lines
13 KiB
Python
442 lines
13 KiB
Python
# ext/declarative/clsregistry.py
|
|
# Copyright (C) 2005-2022 the SQLAlchemy authors and contributors
|
|
# <see AUTHORS file>
|
|
#
|
|
# This module is part of SQLAlchemy and is released under
|
|
# the MIT License: https://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:`_orm.relationship` using strings.
|
|
|
|
"""
|
|
import weakref
|
|
|
|
from . import attributes
|
|
from . import interfaces
|
|
from .descriptor_props import SynonymProperty
|
|
from .properties import ColumnProperty
|
|
from .util import class_mapper
|
|
from .. import exc
|
|
from .. import inspection
|
|
from .. import util
|
|
from ..sql.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, decl_class_registry):
|
|
"""Add a class to the _decl_class_registry associated with the
|
|
given declarative class.
|
|
|
|
"""
|
|
if classname in decl_class_registry:
|
|
# class already exists.
|
|
existing = decl_class_registry[classname]
|
|
if not isinstance(existing, _MultipleClassMarker):
|
|
existing = decl_class_registry[classname] = _MultipleClassMarker(
|
|
[cls, existing]
|
|
)
|
|
else:
|
|
decl_class_registry[classname] = cls
|
|
|
|
try:
|
|
root_module = decl_class_registry["_sa_module_registry"]
|
|
except KeyError:
|
|
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)
|
|
|
|
|
|
def remove_class(classname, cls, decl_class_registry):
|
|
if classname in decl_class_registry:
|
|
existing = decl_class_registry[classname]
|
|
if isinstance(existing, _MultipleClassMarker):
|
|
existing.remove_item(cls)
|
|
else:
|
|
del decl_class_registry[classname]
|
|
|
|
try:
|
|
root_module = decl_class_registry["_sa_module_registry"]
|
|
except KeyError:
|
|
return
|
|
|
|
tokens = cls.__module__.split(".")
|
|
|
|
while tokens:
|
|
token = tokens.pop(0)
|
|
module = root_module.get_module(token)
|
|
for token in tokens:
|
|
module = module.get_module(token)
|
|
module.remove_class(classname, cls)
|
|
|
|
|
|
def _key_is_empty(key, decl_class_registry, test):
|
|
"""test if a key is empty of a certain object.
|
|
|
|
used for unit tests against the registry to see if garbage collection
|
|
is working.
|
|
|
|
"test" is a callable that will be passed an object should return True
|
|
if the given object is the one we were looking for.
|
|
|
|
We can't pass the actual object itself b.c. this is for testing garbage
|
|
collection; the caller will have to have removed references to the
|
|
object itself.
|
|
|
|
"""
|
|
if key not in decl_class_registry:
|
|
return True
|
|
|
|
thing = decl_class_registry[key]
|
|
if isinstance(thing, _MultipleClassMarker):
|
|
for sub_thing in thing.contents:
|
|
if test(sub_thing):
|
|
return False
|
|
else:
|
|
return not test(thing)
|
|
|
|
|
|
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 remove_item(self, cls):
|
|
self._remove_item(weakref.ref(cls))
|
|
|
|
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.discard(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)
|
|
)
|
|
|
|
def remove_class(self, name, cls):
|
|
if name in self.contents:
|
|
existing = self.contents[name]
|
|
existing.remove_item(cls)
|
|
|
|
|
|
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 NameError(
|
|
"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 AttributeError(
|
|
"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):
|
|
__slots__ = (
|
|
"cls",
|
|
"prop",
|
|
"arg",
|
|
"fallback",
|
|
"_dict",
|
|
"_resolvers",
|
|
"favor_tables",
|
|
)
|
|
|
|
def __init__(self, cls, prop, fallback, arg, favor_tables=False):
|
|
self.cls = cls
|
|
self.prop = prop
|
|
self.arg = arg
|
|
self.fallback = fallback
|
|
self._dict = util.PopulateDict(self._access_cls)
|
|
self._resolvers = ()
|
|
self.favor_tables = favor_tables
|
|
|
|
def _access_cls(self, key):
|
|
cls = self.cls
|
|
|
|
manager = attributes.manager_of_class(cls)
|
|
decl_base = manager.registry
|
|
decl_class_registry = decl_base._class_registry
|
|
metadata = decl_base.metadata
|
|
|
|
if self.favor_tables:
|
|
if key in metadata.tables:
|
|
return metadata.tables[key]
|
|
elif key in metadata._schemas:
|
|
return _GetTable(key, cls.metadata)
|
|
|
|
if key in decl_class_registry:
|
|
return _determine_container(key, decl_class_registry[key])
|
|
|
|
if not self.favor_tables:
|
|
if key in metadata.tables:
|
|
return metadata.tables[key]
|
|
elif key in metadata._schemas:
|
|
return _GetTable(key, cls.metadata)
|
|
|
|
if (
|
|
"_sa_module_registry" in decl_class_registry
|
|
and key in decl_class_registry["_sa_module_registry"]
|
|
):
|
|
registry = 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 _raise_for_name(self, name, err):
|
|
util.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, name, self.cls)
|
|
),
|
|
from_=err,
|
|
)
|
|
|
|
def _resolve_name(self):
|
|
name = self.arg
|
|
d = self._dict
|
|
rval = None
|
|
try:
|
|
for token in name.split("."):
|
|
if rval is None:
|
|
rval = d[token]
|
|
else:
|
|
rval = getattr(rval, token)
|
|
except KeyError as err:
|
|
self._raise_for_name(name, err)
|
|
except NameError as n:
|
|
self._raise_for_name(n.args[0], n)
|
|
else:
|
|
if isinstance(rval, _GetColumns):
|
|
return rval.cls
|
|
else:
|
|
return rval
|
|
|
|
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:
|
|
self._raise_for_name(n.args[0], n)
|
|
|
|
|
|
_fallback_dict = None
|
|
|
|
|
|
def _resolver(cls, prop):
|
|
|
|
global _fallback_dict
|
|
|
|
if _fallback_dict is None:
|
|
import sqlalchemy
|
|
from sqlalchemy.orm import foreign, remote
|
|
|
|
_fallback_dict = util.immutabledict(sqlalchemy.__dict__).union(
|
|
{"foreign": foreign, "remote": remote}
|
|
)
|
|
|
|
def resolve_arg(arg, favor_tables=False):
|
|
return _class_resolver(
|
|
cls, prop, _fallback_dict, arg, favor_tables=favor_tables
|
|
)
|
|
|
|
def resolve_name(arg):
|
|
return _class_resolver(cls, prop, _fallback_dict, arg)._resolve_name
|
|
|
|
return resolve_name, resolve_arg
|