new

.venv/lib/python3.9/site-packages/fastapi/concurrency.py

@@ -0,0 +1,51 @@
+from typing import Any, Callable
+
+from starlette.concurrency import iterate_in_threadpool as iterate_in_threadpool  # noqa
+from starlette.concurrency import run_in_threadpool as run_in_threadpool  # noqa
+from starlette.concurrency import (  # noqa
+    run_until_first_complete as run_until_first_complete,
+)
+
+asynccontextmanager_error_message = """
+FastAPI's contextmanager_in_threadpool require Python 3.7 or above,
+or the backport for Python 3.6, installed with:
+    pip install async-generator
+"""
+
+
+def _fake_asynccontextmanager(func: Callable[..., Any]) -> Callable[..., Any]:
+    def raiser(*args: Any, **kwargs: Any) -> Any:
+        raise RuntimeError(asynccontextmanager_error_message)
+
+    return raiser
+
+
+try:
+    from contextlib import asynccontextmanager as asynccontextmanager  # type: ignore
+except ImportError:
+    try:
+        from async_generator import (  # type: ignore  # isort: skip
+            asynccontextmanager as asynccontextmanager,
+        )
+    except ImportError:  # pragma: no cover
+        asynccontextmanager = _fake_asynccontextmanager
+
+try:
+    from contextlib import AsyncExitStack as AsyncExitStack  # type: ignore
+except ImportError:
+    try:
+        from async_exit_stack import AsyncExitStack as AsyncExitStack  # type: ignore
+    except ImportError:  # pragma: no cover
+        AsyncExitStack = None  # type: ignore
+
+
+@asynccontextmanager  # type: ignore
+async def contextmanager_in_threadpool(cm: Any) -> Any:
+    try:
+        yield await run_in_threadpool(cm.__enter__)
+    except Exception as e:
+        ok = await run_in_threadpool(cm.__exit__, type(e), e, None)
+        if not ok:
+            raise e
+    else:
+        await run_in_threadpool(cm.__exit__, None, None, None)