/usr/lib/python2.7/dist-packages/sqlalchemy/ext/declarative/clsregistry.py is in python-sqlalchemy 0.9.8+dfsg-0.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 | # ext/declarative/clsregistry.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
"""Routines to handle the string class registry used by declarative.
This system allows specification of classes and expressions used in
:func:`.relationship` using strings.
"""
from ...orm.properties import ColumnProperty, RelationshipProperty, \
SynonymProperty
from ...schema import _get_table_key
from ...orm import class_mapper, interfaces
from ... import util
from ... import inspection
from ... import exc
import weakref
# 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):
"""Add a class to the _decl_class_registry associated with the
given declarative class.
"""
if classname in cls._decl_class_registry:
# class already exists.
existing = cls._decl_class_registry[classname]
if not isinstance(existing, _MultipleClassMarker):
existing = \
cls._decl_class_registry[classname] = \
_MultipleClassMarker([cls, existing])
else:
cls._decl_class_registry[classname] = cls
try:
root_module = cls._decl_class_registry['_sa_module_registry']
except KeyError:
cls._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)
class _MultipleClassMarker(object):
"""refers to multiple classes of the same name
within _decl_class_registry.
"""
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 __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.remove(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.
"""
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))
class _ModNS(object):
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 AttributeError("Module %r has no mapped classes "
"registered under the name %r" % (
self.__parent.name, key))
class _GetColumns(object):
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 exc.InvalidRequestError(
"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):
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):
def __init__(self, cls, prop, fallback, arg):
self.cls = cls
self.prop = prop
self.arg = self._declarative_arg = arg
self.fallback = fallback
self._dict = util.PopulateDict(self._access_cls)
self._resolvers = ()
def _access_cls(self, key):
cls = self.cls
if key in cls._decl_class_registry:
return _determine_container(key, cls._decl_class_registry[key])
elif key in cls.metadata.tables:
return cls.metadata.tables[key]
elif key in cls.metadata._schemas:
return _GetTable(key, cls.metadata)
elif '_sa_module_registry' in cls._decl_class_registry and \
key in cls._decl_class_registry['_sa_module_registry']:
registry = cls._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 __call__(self):
try:
x = eval(self.arg, globals(), self._dict)
if isinstance(x, _GetColumns):
return x.cls
else:
return x
except NameError as n:
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, n.args[0], self.cls)
)
def _resolver(cls, prop):
import sqlalchemy
from sqlalchemy.orm import foreign, remote
fallback = sqlalchemy.__dict__.copy()
fallback.update({'foreign': foreign, 'remote': remote})
def resolve_arg(arg):
return _class_resolver(cls, prop, fallback, arg)
return resolve_arg
def _deferred_relationship(cls, prop):
if isinstance(prop, RelationshipProperty):
resolve_arg = _resolver(cls, prop)
for attr in ('argument', 'order_by', 'primaryjoin', 'secondaryjoin',
'secondary', '_user_defined_foreign_keys', 'remote_side'):
v = getattr(prop, attr)
if isinstance(v, util.string_types):
setattr(prop, attr, resolve_arg(v))
if prop.backref and isinstance(prop.backref, tuple):
key, kwargs = prop.backref
for attr in ('primaryjoin', 'secondaryjoin', 'secondary',
'foreign_keys', 'remote_side', 'order_by'):
if attr in kwargs and isinstance(kwargs[attr], str):
kwargs[attr] = resolve_arg(kwargs[attr])
return prop
|