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Diffstat (limited to 'venv/lib/python3.11/site-packages/sqlalchemy/engine/util.py')
| -rw-r--r-- | venv/lib/python3.11/site-packages/sqlalchemy/engine/util.py | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/venv/lib/python3.11/site-packages/sqlalchemy/engine/util.py b/venv/lib/python3.11/site-packages/sqlalchemy/engine/util.py new file mode 100644 index 0000000..186ca4c --- /dev/null +++ b/venv/lib/python3.11/site-packages/sqlalchemy/engine/util.py @@ -0,0 +1,167 @@ +# engine/util.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 + +from __future__ import annotations + +import typing +from typing import Any +from typing import Callable +from typing import Optional +from typing import TypeVar + +from .. import exc +from .. import util +from ..util._has_cy import HAS_CYEXTENSION +from ..util.typing import Protocol +from ..util.typing import Self + +if typing.TYPE_CHECKING or not HAS_CYEXTENSION: + from ._py_util import _distill_params_20 as _distill_params_20 + from ._py_util import _distill_raw_params as _distill_raw_params +else: + from sqlalchemy.cyextension.util import ( # noqa: F401 + _distill_params_20 as _distill_params_20, + ) + from sqlalchemy.cyextension.util import ( # noqa: F401 + _distill_raw_params as _distill_raw_params, + ) + +_C = TypeVar("_C", bound=Callable[[], Any]) + + +def connection_memoize(key: str) -> Callable[[_C], _C]: + """Decorator, memoize a function in a connection.info stash. + + Only applicable to functions which take no arguments other than a + connection. The memo will be stored in ``connection.info[key]``. + """ + + @util.decorator + def decorated(fn, self, connection): # type: ignore + connection = connection.connect() + try: + return connection.info[key] + except KeyError: + connection.info[key] = val = fn(self, connection) + return val + + return decorated + + +class _TConsSubject(Protocol): + _trans_context_manager: Optional[TransactionalContext] + + +class TransactionalContext: + """Apply Python context manager behavior to transaction objects. + + Performs validation to ensure the subject of the transaction is not + used if the transaction were ended prematurely. + + """ + + __slots__ = ("_outer_trans_ctx", "_trans_subject", "__weakref__") + + _trans_subject: Optional[_TConsSubject] + + def _transaction_is_active(self) -> bool: + raise NotImplementedError() + + def _transaction_is_closed(self) -> bool: + raise NotImplementedError() + + def _rollback_can_be_called(self) -> bool: + """indicates the object is in a state that is known to be acceptable + for rollback() to be called. + + This does not necessarily mean rollback() will succeed or not raise + an error, just that there is currently no state detected that indicates + rollback() would fail or emit warnings. + + It also does not mean that there's a transaction in progress, as + it is usually safe to call rollback() even if no transaction is + present. + + .. versionadded:: 1.4.28 + + """ + raise NotImplementedError() + + def _get_subject(self) -> _TConsSubject: + raise NotImplementedError() + + def commit(self) -> None: + raise NotImplementedError() + + def rollback(self) -> None: + raise NotImplementedError() + + def close(self) -> None: + raise NotImplementedError() + + @classmethod + def _trans_ctx_check(cls, subject: _TConsSubject) -> None: + trans_context = subject._trans_context_manager + if trans_context: + if not trans_context._transaction_is_active(): + raise exc.InvalidRequestError( + "Can't operate on closed transaction inside context " + "manager. Please complete the context manager " + "before emitting further commands." + ) + + def __enter__(self) -> Self: + subject = self._get_subject() + + # none for outer transaction, may be non-None for nested + # savepoint, legacy nesting cases + trans_context = subject._trans_context_manager + self._outer_trans_ctx = trans_context + + self._trans_subject = subject + subject._trans_context_manager = self + return self + + def __exit__(self, type_: Any, value: Any, traceback: Any) -> None: + subject = getattr(self, "_trans_subject", None) + + # simplistically we could assume that + # "subject._trans_context_manager is self". However, any calling + # code that is manipulating __exit__ directly would break this + # assumption. alembic context manager + # is an example of partial use that just calls __exit__ and + # not __enter__ at the moment. it's safe to assume this is being done + # in the wild also + out_of_band_exit = ( + subject is None or subject._trans_context_manager is not self + ) + + if type_ is None and self._transaction_is_active(): + try: + self.commit() + except: + with util.safe_reraise(): + if self._rollback_can_be_called(): + self.rollback() + finally: + if not out_of_band_exit: + assert subject is not None + subject._trans_context_manager = self._outer_trans_ctx + self._trans_subject = self._outer_trans_ctx = None + else: + try: + if not self._transaction_is_active(): + if not self._transaction_is_closed(): + self.close() + else: + if self._rollback_can_be_called(): + self.rollback() + finally: + if not out_of_band_exit: + assert subject is not None + subject._trans_context_manager = self._outer_trans_ctx + self._trans_subject = self._outer_trans_ctx = None |