init

.venv/lib/python3.8/site-packages/black/concurrency.py

@@ -0,0 +1,57 @@
+import asyncio
+import logging
+import sys
+from typing import Any, Iterable
+
+from black.output import err
+
+
+def maybe_install_uvloop() -> None:
+    """If our environment has uvloop installed we use it.
+
+    This is called only from command-line entry points to avoid
+    interfering with the parent process if Black is used as a library.
+
+    """
+    try:
+        import uvloop
+
+        uvloop.install()
+    except ImportError:
+        pass
+
+
+def cancel(tasks: Iterable["asyncio.Task[Any]"]) -> None:
+    """asyncio signal handler that cancels all `tasks` and reports to stderr."""
+    err("Aborted!")
+    for task in tasks:
+        task.cancel()
+
+
+def shutdown(loop: asyncio.AbstractEventLoop) -> None:
+    """Cancel all pending tasks on `loop`, wait for them, and close the loop."""
+    try:
+        if sys.version_info[:2] >= (3, 7):
+            all_tasks = asyncio.all_tasks
+        else:
+            all_tasks = asyncio.Task.all_tasks
+        # This part is borrowed from asyncio/runners.py in Python 3.7b2.
+        to_cancel = [task for task in all_tasks(loop) if not task.done()]
+        if not to_cancel:
+            return
+
+        for task in to_cancel:
+            task.cancel()
+        if sys.version_info >= (3, 7):
+            loop.run_until_complete(asyncio.gather(*to_cancel, return_exceptions=True))
+        else:
+            loop.run_until_complete(
+                asyncio.gather(*to_cancel, loop=loop, return_exceptions=True)
+            )
+    finally:
+        # `concurrent.futures.Future` objects cannot be cancelled once they
+        # are already running. There might be some when the `shutdown()` happened.
+        # Silence their logger's spew about the event loop being closed.
+        cf_logger = logging.getLogger("concurrent.futures")
+        cf_logger.setLevel(logging.CRITICAL)
+        loop.close()