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# util/_preloaded.py
# Copyright (C) 2005-2023 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
# mypy: allow-untyped-defs, allow-untyped-calls
"""supplies the "preloaded" registry to resolve circular module imports at
runtime.
"""
from __future__ import annotations
import sys
from typing import Any
from typing import Callable
from typing import TYPE_CHECKING
from typing import TypeVar
_FN = TypeVar("_FN", bound=Callable[..., Any])
if TYPE_CHECKING:
from sqlalchemy import dialects as _dialects
from sqlalchemy import orm as _orm
from sqlalchemy.engine import cursor as _engine_cursor
from sqlalchemy.engine import default as _engine_default
from sqlalchemy.engine import reflection as _engine_reflection
from sqlalchemy.engine import result as _engine_result
from sqlalchemy.engine import url as _engine_url
from sqlalchemy.orm import attributes as _orm_attributes
from sqlalchemy.orm import base as _orm_base
from sqlalchemy.orm import clsregistry as _orm_clsregistry
from sqlalchemy.orm import decl_api as _orm_decl_api
from sqlalchemy.orm import decl_base as _orm_decl_base
from sqlalchemy.orm import dependency as _orm_dependency
from sqlalchemy.orm import descriptor_props as _orm_descriptor_props
from sqlalchemy.orm import mapperlib as _orm_mapper
from sqlalchemy.orm import properties as _orm_properties
from sqlalchemy.orm import relationships as _orm_relationships
from sqlalchemy.orm import session as _orm_session
from sqlalchemy.orm import state as _orm_state
from sqlalchemy.orm import strategies as _orm_strategies
from sqlalchemy.orm import strategy_options as _orm_strategy_options
from sqlalchemy.orm import util as _orm_util
from sqlalchemy.sql import default_comparator as _sql_default_comparator
from sqlalchemy.sql import dml as _sql_dml
from sqlalchemy.sql import elements as _sql_elements
from sqlalchemy.sql import functions as _sql_functions
from sqlalchemy.sql import naming as _sql_naming
from sqlalchemy.sql import schema as _sql_schema
from sqlalchemy.sql import selectable as _sql_selectable
from sqlalchemy.sql import sqltypes as _sql_sqltypes
from sqlalchemy.sql import traversals as _sql_traversals
from sqlalchemy.sql import util as _sql_util
# sigh, appease mypy 0.971 which does not accept imports as instance
# variables of a module
dialects = _dialects
engine_cursor = _engine_cursor
engine_default = _engine_default
engine_reflection = _engine_reflection
engine_result = _engine_result
engine_url = _engine_url
orm_clsregistry = _orm_clsregistry
orm_base = _orm_base
orm = _orm
orm_attributes = _orm_attributes
orm_decl_api = _orm_decl_api
orm_decl_base = _orm_decl_base
orm_descriptor_props = _orm_descriptor_props
orm_dependency = _orm_dependency
orm_mapper = _orm_mapper
orm_properties = _orm_properties
orm_relationships = _orm_relationships
orm_session = _orm_session
orm_strategies = _orm_strategies
orm_strategy_options = _orm_strategy_options
orm_state = _orm_state
orm_util = _orm_util
sql_default_comparator = _sql_default_comparator
sql_dml = _sql_dml
sql_elements = _sql_elements
sql_functions = _sql_functions
sql_naming = _sql_naming
sql_selectable = _sql_selectable
sql_traversals = _sql_traversals
sql_schema = _sql_schema
sql_sqltypes = _sql_sqltypes
sql_util = _sql_util
class _ModuleRegistry:
"""Registry of modules to load in a package init file.
To avoid potential thread safety issues for imports that are deferred
in a function, like https://bugs.python.org/issue38884, these modules
are added to the system module cache by importing them after the packages
has finished initialization.
A global instance is provided under the name :attr:`.preloaded`. Use
the function :func:`.preload_module` to register modules to load and
:meth:`.import_prefix` to load all the modules that start with the
given path.
While the modules are loaded in the global module cache, it's advisable
to access them using :attr:`.preloaded` to ensure that it was actually
registered. Each registered module is added to the instance ``__dict__``
in the form `<package>_<module>`, omitting ``sqlalchemy`` from the package
name. Example: ``sqlalchemy.sql.util`` becomes ``preloaded.sql_util``.
"""
def __init__(self, prefix="sqlalchemy."):
self.module_registry = set()
self.prefix = prefix
def preload_module(self, *deps: str) -> Callable[[_FN], _FN]:
"""Adds the specified modules to the list to load.
This method can be used both as a normal function and as a decorator.
No change is performed to the decorated object.
"""
self.module_registry.update(deps)
return lambda fn: fn
def import_prefix(self, path: str) -> None:
"""Resolve all the modules in the registry that start with the
specified path.
"""
for module in self.module_registry:
if self.prefix:
key = module.split(self.prefix)[-1].replace(".", "_")
else:
key = module
if (
not path or module.startswith(path)
) and key not in self.__dict__:
__import__(module, globals(), locals())
self.__dict__[key] = globals()[key] = sys.modules[module]
_reg = _ModuleRegistry()
preload_module = _reg.preload_module
import_prefix = _reg.import_prefix
# this appears to do absolutely nothing for any version of mypy
# if TYPE_CHECKING:
# def __getattr__(key: str) -> ModuleType:
# ...
|
