1 files changed, 290 insertions, 0 deletions
diff --git a/venv/lib/python3.11/site-packages/sqlalchemy/util/_concurrency_py3k.py b/venv/lib/python3.11/site-packages/sqlalchemy/util/_concurrency_py3k.py
new file mode 100644
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+++ b/venv/lib/python3.11/site-packages/sqlalchemy/util/_concurrency_py3k.py
@@ -0,0 +1,290 @@
+# util/_concurrency_py3k.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
+# mypy: allow-untyped-defs, allow-untyped-calls
+
+from __future__ import annotations
+
+import asyncio
+from contextvars import Context
+import sys
+import typing
+from typing import Any
+from typing import Awaitable
+from typing import Callable
+from typing import Coroutine
+from typing import Optional
+from typing import TYPE_CHECKING
+from typing import TypeVar
+from typing import Union
+
+from .langhelpers import memoized_property
+from .. import exc
+from ..util import py311
+from ..util.typing import Literal
+from ..util.typing import Protocol
+from ..util.typing import Self
+from ..util.typing import TypeGuard
+
+_T = TypeVar("_T")
+
+if typing.TYPE_CHECKING:
+
+    class greenlet(Protocol):
+        dead: bool
+        gr_context: Optional[Context]
+
+        def __init__(self, fn: Callable[..., Any], driver: greenlet): ...
+
+        def throw(self, *arg: Any) -> Any:
+            return None
+
+        def switch(self, value: Any) -> Any:
+            return None
+
+    def getcurrent() -> greenlet: ...
+
+else:
+    from greenlet import getcurrent
+    from greenlet import greenlet
+
+
+# If greenlet.gr_context is present in current version of greenlet,
+# it will be set with the current context on creation.
+# Refs: https://github.com/python-greenlet/greenlet/pull/198
+_has_gr_context = hasattr(getcurrent(), "gr_context")
+
+
+def is_exit_exception(e: BaseException) -> bool:
+    # note asyncio.CancelledError is already BaseException
+    # so was an exit exception in any case
+    return not isinstance(e, Exception) or isinstance(
+        e, (asyncio.TimeoutError, asyncio.CancelledError)
+    )
+
+
+# implementation based on snaury gist at
+# https://gist.github.com/snaury/202bf4f22c41ca34e56297bae5f33fef
+# Issue for context: https://github.com/python-greenlet/greenlet/issues/173
+
+
+class _AsyncIoGreenlet(greenlet):
+    dead: bool
+
+    def __init__(self, fn: Callable[..., Any], driver: greenlet):
+        greenlet.__init__(self, fn, driver)
+        self.driver = driver
+        if _has_gr_context:
+            self.gr_context = driver.gr_context
+
+
+_T_co = TypeVar("_T_co", covariant=True)
+
+if TYPE_CHECKING:
+
+    def iscoroutine(
+        awaitable: Awaitable[_T_co],
+    ) -> TypeGuard[Coroutine[Any, Any, _T_co]]: ...
+
+else:
+    iscoroutine = asyncio.iscoroutine
+
+
+def _safe_cancel_awaitable(awaitable: Awaitable[Any]) -> None:
+    # https://docs.python.org/3/reference/datamodel.html#coroutine.close
+
+    if iscoroutine(awaitable):
+        awaitable.close()
+
+
+def in_greenlet() -> bool:
+    current = getcurrent()
+    return isinstance(current, _AsyncIoGreenlet)
+
+
+def await_only(awaitable: Awaitable[_T]) -> _T:
+    """Awaits an async function in a sync method.
+
+    The sync method must be inside a :func:`greenlet_spawn` context.
+    :func:`await_only` calls cannot be nested.
+
+    :param awaitable: The coroutine to call.
+
+    """
+    # this is called in the context greenlet while running fn
+    current = getcurrent()
+    if not isinstance(current, _AsyncIoGreenlet):
+        _safe_cancel_awaitable(awaitable)
+
+        raise exc.MissingGreenlet(
+            "greenlet_spawn has not been called; can't call await_only() "
+            "here. Was IO attempted in an unexpected place?"
+        )
+
+    # returns the control to the driver greenlet passing it
+    # a coroutine to run. Once the awaitable is done, the driver greenlet
+    # switches back to this greenlet with the result of awaitable that is
+    # then returned to the caller (or raised as error)
+    return current.driver.switch(awaitable)  # type: ignore[no-any-return]
+
+
+def await_fallback(awaitable: Awaitable[_T]) -> _T:
+    """Awaits an async function in a sync method.
+
+    The sync method must be inside a :func:`greenlet_spawn` context.
+    :func:`await_fallback` calls cannot be nested.
+
+    :param awaitable: The coroutine to call.
+
+    .. deprecated:: 2.0.24 The ``await_fallback()`` function will be removed
+       in SQLAlchemy 2.1.  Use :func:`_util.await_only` instead, running the
+       function / program / etc. within a top-level greenlet that is set up
+       using :func:`_util.greenlet_spawn`.
+
+    """
+
+    # this is called in the context greenlet while running fn
+    current = getcurrent()
+    if not isinstance(current, _AsyncIoGreenlet):
+        loop = get_event_loop()
+        if loop.is_running():
+            _safe_cancel_awaitable(awaitable)
+
+            raise exc.MissingGreenlet(
+                "greenlet_spawn has not been called and asyncio event "
+                "loop is already running; can't call await_fallback() here. "
+                "Was IO attempted in an unexpected place?"
+            )
+        return loop.run_until_complete(awaitable)
+
+    return current.driver.switch(awaitable)  # type: ignore[no-any-return]
+
+
+async def greenlet_spawn(
+    fn: Callable[..., _T],
+    *args: Any,
+    _require_await: bool = False,
+    **kwargs: Any,
+) -> _T:
+    """Runs a sync function ``fn`` in a new greenlet.
+
+    The sync function can then use :func:`await_only` to wait for async
+    functions.
+
+    :param fn: The sync callable to call.
+    :param \\*args: Positional arguments to pass to the ``fn`` callable.
+    :param \\*\\*kwargs: Keyword arguments to pass to the ``fn`` callable.
+    """
+
+    result: Any
+    context = _AsyncIoGreenlet(fn, getcurrent())
+    # runs the function synchronously in gl greenlet. If the execution
+    # is interrupted by await_only, context is not dead and result is a
+    # coroutine to wait. If the context is dead the function has
+    # returned, and its result can be returned.
+    switch_occurred = False
+    try:
+        result = context.switch(*args, **kwargs)
+        while not context.dead:
+            switch_occurred = True
+            try:
+                # wait for a coroutine from await_only and then return its
+                # result back to it.
+                value = await result
+            except BaseException:
+                # this allows an exception to be raised within
+                # the moderated greenlet so that it can continue
+                # its expected flow.
+                result = context.throw(*sys.exc_info())
+            else:
+                result = context.switch(value)
+    finally:
+        # clean up to avoid cycle resolution by gc
+        del context.driver
+    if _require_await and not switch_occurred:
+        raise exc.AwaitRequired(
+            "The current operation required an async execution but none was "
+            "detected. This will usually happen when using a non compatible "
+            "DBAPI driver. Please ensure that an async DBAPI is used."
+        )
+    return result  # type: ignore[no-any-return]
+
+
+class AsyncAdaptedLock:
+    @memoized_property
+    def mutex(self) -> asyncio.Lock:
+        # there should not be a race here for coroutines creating the
+        # new lock as we are not using await, so therefore no concurrency
+        return asyncio.Lock()
+
+    def __enter__(self) -> bool:
+        # await is used to acquire the lock only after the first calling
+        # coroutine has created the mutex.
+        return await_fallback(self.mutex.acquire())
+
+    def __exit__(self, *arg: Any, **kw: Any) -> None:
+        self.mutex.release()
+
+
+def get_event_loop() -> asyncio.AbstractEventLoop:
+    """vendor asyncio.get_event_loop() for python 3.7 and above.
+
+    Python 3.10 deprecates get_event_loop() as a standalone.
+
+    """
+    try:
+        return asyncio.get_running_loop()
+    except RuntimeError:
+        # avoid "During handling of the above exception, another exception..."
+        pass
+    return asyncio.get_event_loop_policy().get_event_loop()
+
+
+if not TYPE_CHECKING and py311:
+    _Runner = asyncio.Runner
+else:
+
+    class _Runner:
+        """Runner implementation for test only"""
+
+        _loop: Union[None, asyncio.AbstractEventLoop, Literal[False]]
+
+        def __init__(self) -> None:
+            self._loop = None
+
+        def __enter__(self) -> Self:
+            self._lazy_init()
+            return self
+
+        def __exit__(self, exc_type: Any, exc_val: Any, exc_tb: Any) -> None:
+            self.close()
+
+        def close(self) -> None:
+            if self._loop:
+                try:
+                    self._loop.run_until_complete(
+                        self._loop.shutdown_asyncgens()
+                    )
+                finally:
+                    self._loop.close()
+                    self._loop = False
+
+        def get_loop(self) -> asyncio.AbstractEventLoop:
+            """Return embedded event loop."""
+            self._lazy_init()
+            assert self._loop
+            return self._loop
+
+        def run(self, coro: Coroutine[Any, Any, _T]) -> _T:
+            self._lazy_init()
+            assert self._loop
+            return self._loop.run_until_complete(coro)
+
+        def _lazy_init(self) -> None:
+            if self._loop is False:
+                raise RuntimeError("Runner is closed")
+            if self._loop is None:
+                self._loop = asyncio.new_event_loop()