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Diffstat (limited to 'venv/lib/python3.11/site-packages/sqlalchemy/orm/clsregistry.py')
| -rw-r--r-- | venv/lib/python3.11/site-packages/sqlalchemy/orm/clsregistry.py | 570 |
1 files changed, 570 insertions, 0 deletions
diff --git a/venv/lib/python3.11/site-packages/sqlalchemy/orm/clsregistry.py b/venv/lib/python3.11/site-packages/sqlalchemy/orm/clsregistry.py new file mode 100644 index 0000000..26113d8 --- /dev/null +++ b/venv/lib/python3.11/site-packages/sqlalchemy/orm/clsregistry.py @@ -0,0 +1,570 @@ +# orm/clsregistry.py +# Copyright (C) 2005-2024 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. + +""" + +from __future__ import annotations + +import re +from typing import Any +from typing import Callable +from typing import cast +from typing import Dict +from typing import Generator +from typing import Iterable +from typing import List +from typing import Mapping +from typing import MutableMapping +from typing import NoReturn +from typing import Optional +from typing import Set +from typing import Tuple +from typing import Type +from typing import TYPE_CHECKING +from typing import TypeVar +from typing import Union +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 +from ..util.typing import CallableReference + +if TYPE_CHECKING: + from .relationships import RelationshipProperty + from ..sql.schema import MetaData + from ..sql.schema import Table + +_T = TypeVar("_T", bound=Any) + +_ClsRegistryType = MutableMapping[str, Union[type, "ClsRegistryToken"]] + +# 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[ClsRegistryToken] = set() + + +def add_class( + classname: str, cls: Type[_T], decl_class_registry: _ClsRegistryType +) -> None: + """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, cast("Type[Any]", existing)] + ) + else: + decl_class_registry[classname] = cls + + try: + root_module = cast( + _ModuleMarker, 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) + + try: + module.add_class(classname, cls) + except AttributeError as ae: + if not isinstance(module, _ModuleMarker): + raise exc.InvalidRequestError( + f'name "{classname}" matches both a ' + "class name and a module name" + ) from ae + else: + raise + + +def remove_class( + classname: str, cls: Type[Any], decl_class_registry: _ClsRegistryType +) -> None: + 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 = cast( + _ModuleMarker, 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) + try: + module.remove_class(classname, cls) + except AttributeError: + if not isinstance(module, _ModuleMarker): + pass + else: + raise + + +def _key_is_empty( + key: str, + decl_class_registry: _ClsRegistryType, + test: Callable[[Any], bool], +) -> bool: + """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: + raise NotImplementedError("unknown codepath") + else: + return not test(thing) + + +class ClsRegistryToken: + """an object that can be in the registry._class_registry as a value.""" + + __slots__ = () + + +class _MultipleClassMarker(ClsRegistryToken): + """refers to multiple classes of the same name + within _decl_class_registry. + + """ + + __slots__ = "on_remove", "contents", "__weakref__" + + contents: Set[weakref.ref[Type[Any]]] + on_remove: CallableReference[Optional[Callable[[], None]]] + + def __init__( + self, + classes: Iterable[Type[Any]], + on_remove: Optional[Callable[[], None]] = None, + ): + self.on_remove = on_remove + self.contents = { + weakref.ref(item, self._remove_item) for item in classes + } + _registries.add(self) + + def remove_item(self, cls: Type[Any]) -> None: + self._remove_item(weakref.ref(cls)) + + def __iter__(self) -> Generator[Optional[Type[Any]], None, None]: + return (ref() for ref in self.contents) + + def attempt_get(self, path: List[str], key: str) -> Type[Any]: + 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: weakref.ref[Type[Any]]) -> None: + self.contents.discard(ref) + if not self.contents: + _registries.discard(self) + if self.on_remove: + self.on_remove() + + def add_item(self, item: Type[Any]) -> None: + # protect against class registration race condition against + # asynchronous garbage collection calling _remove_item, + # [ticket:3208] and [ticket:10782] + modules = { + cls.__module__ + for cls in [ref() for ref in list(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(ClsRegistryToken): + """Refers to a module name within + _decl_class_registry. + + """ + + __slots__ = "parent", "name", "contents", "mod_ns", "path", "__weakref__" + + parent: Optional[_ModuleMarker] + contents: Dict[str, Union[_ModuleMarker, _MultipleClassMarker]] + mod_ns: _ModNS + path: List[str] + + def __init__(self, name: str, parent: Optional[_ModuleMarker]): + 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: str) -> bool: + return name in self.contents + + def __getitem__(self, name: str) -> ClsRegistryToken: + return self.contents[name] + + def _remove_item(self, name: str) -> None: + 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: str) -> Union[_ModNS, Type[Any]]: + return self.mod_ns.__getattr__(key) + + def get_module(self, name: str) -> _ModuleMarker: + if name not in self.contents: + marker = _ModuleMarker(name, self) + self.contents[name] = marker + else: + marker = cast(_ModuleMarker, self.contents[name]) + return marker + + def add_class(self, name: str, cls: Type[Any]) -> None: + if name in self.contents: + existing = cast(_MultipleClassMarker, self.contents[name]) + try: + existing.add_item(cls) + except AttributeError as ae: + if not isinstance(existing, _MultipleClassMarker): + raise exc.InvalidRequestError( + f'name "{name}" matches both a ' + "class name and a module name" + ) from ae + else: + raise + else: + existing = self.contents[name] = _MultipleClassMarker( + [cls], on_remove=lambda: self._remove_item(name) + ) + + def remove_class(self, name: str, cls: Type[Any]) -> None: + if name in self.contents: + existing = cast(_MultipleClassMarker, self.contents[name]) + existing.remove_item(cls) + + +class _ModNS: + __slots__ = ("__parent",) + + __parent: _ModuleMarker + + def __init__(self, parent: _ModuleMarker): + self.__parent = parent + + def __getattr__(self, key: str) -> Union[_ModNS, Type[Any]]: + 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: + __slots__ = ("cls",) + + cls: Type[Any] + + def __init__(self, cls: Type[Any]): + self.cls = cls + + def __getattr__(self, key: str) -> Any: + 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.NotExtension.NOT_EXTENSION: + assert isinstance(desc, attributes.QueryableAttribute) + 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: + __slots__ = "key", "metadata" + + key: str + metadata: MetaData + + def __init__(self, key: str, metadata: MetaData): + self.key = key + self.metadata = metadata + + def __getattr__(self, key: str) -> Table: + return self.metadata.tables[_get_table_key(key, self.key)] + + +def _determine_container(key: str, value: Any) -> _GetColumns: + if isinstance(value, _MultipleClassMarker): + value = value.attempt_get([], key) + return _GetColumns(value) + + +class _class_resolver: + __slots__ = ( + "cls", + "prop", + "arg", + "fallback", + "_dict", + "_resolvers", + "favor_tables", + ) + + cls: Type[Any] + prop: RelationshipProperty[Any] + fallback: Mapping[str, Any] + arg: str + favor_tables: bool + _resolvers: Tuple[Callable[[str], Any], ...] + + def __init__( + self, + cls: Type[Any], + prop: RelationshipProperty[Any], + fallback: Mapping[str, Any], + arg: str, + favor_tables: bool = 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: str) -> Any: + cls = self.cls + + manager = attributes.manager_of_class(cls) + decl_base = manager.registry + assert decl_base is not None + 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, getattr(cls, "metadata", 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, getattr(cls, "metadata", metadata)) + + if "_sa_module_registry" in decl_class_registry and key in cast( + _ModuleMarker, decl_class_registry["_sa_module_registry"] + ): + registry = cast( + _ModuleMarker, 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: str, err: Exception) -> NoReturn: + generic_match = re.match(r"(.+)\[(.+)\]", name) + + if generic_match: + clsarg = generic_match.group(2).strip("'") + raise exc.InvalidRequestError( + f"When initializing mapper {self.prop.parent}, " + f'expression "relationship({self.arg!r})" seems to be ' + "using a generic class as the argument to relationship(); " + "please state the generic argument " + "using an annotation, e.g. " + f'"{self.prop.key}: Mapped[{generic_match.group(1)}' + f"['{clsarg}']] = relationship()\"" + ) from err + else: + 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) -> Union[Table, Type[Any], _ModNS]: + 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: + if TYPE_CHECKING: + assert isinstance(rval, (type, Table, _ModNS)) + return rval + + def __call__(self) -> Any: + 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: Mapping[str, Any] = None # type: ignore + + +def _resolver(cls: Type[Any], prop: RelationshipProperty[Any]) -> Tuple[ + Callable[[str], Callable[[], Union[Type[Any], Table, _ModNS]]], + Callable[[str, bool], _class_resolver], +]: + global _fallback_dict + + if _fallback_dict is None: + import sqlalchemy + from . import foreign + from . import remote + + _fallback_dict = util.immutabledict(sqlalchemy.__dict__).union( + {"foreign": foreign, "remote": remote} + ) + + def resolve_arg(arg: str, favor_tables: bool = False) -> _class_resolver: + return _class_resolver( + cls, prop, _fallback_dict, arg, favor_tables=favor_tables + ) + + def resolve_name( + arg: str, + ) -> Callable[[], Union[Type[Any], Table, _ModNS]]: + return _class_resolver(cls, prop, _fallback_dict, arg)._resolve_name + + return resolve_name, resolve_arg |