intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 74 insertions, 0 deletions

diff --git a/contrib/tools/python3/src/Lib/asyncio/runners.py b/contrib/tools/python3/src/Lib/asyncio/runners.py
new file mode 100644
index 0000000000..6920acba38
--- /dev/null
+++ b/contrib/tools/python3/src/Lib/asyncio/runners.py
@@ -0,0 +1,74 @@
+__all__ = 'run',
+
+from . import coroutines
+from . import events
+from . import tasks
+
+
+def run(main, *, debug=None):
+    """Execute the coroutine and return the result.
+
+    This function runs the passed coroutine, taking care of
+    managing the asyncio event loop and finalizing asynchronous
+    generators.
+
+    This function cannot be called when another asyncio event loop is
+    running in the same thread.
+
+    If debug is True, the event loop will be run in debug mode.
+
+    This function always creates a new event loop and closes it at the end.
+    It should be used as a main entry point for asyncio programs, and should
+    ideally only be called once.
+
+    Example:
+
+        async def main():
+            await asyncio.sleep(1)
+            print('hello')
+
+        asyncio.run(main())
+    """
+    if events._get_running_loop() is not None:
+        raise RuntimeError(
+            "asyncio.run() cannot be called from a running event loop")
+
+    if not coroutines.iscoroutine(main):
+        raise ValueError("a coroutine was expected, got {!r}".format(main))
+
+    loop = events.new_event_loop()
+    try:
+        events.set_event_loop(loop)
+        if debug is not None:
+            loop.set_debug(debug)
+        return loop.run_until_complete(main)
+    finally:
+        try:
+            _cancel_all_tasks(loop)
+            loop.run_until_complete(loop.shutdown_asyncgens())
+            loop.run_until_complete(loop.shutdown_default_executor())
+        finally:
+            events.set_event_loop(None)
+            loop.close()
+
+
+def _cancel_all_tasks(loop):
+    to_cancel = tasks.all_tasks(loop)
+    if not to_cancel:
+        return
+
+    for task in to_cancel:
+        task.cancel()
+
+    loop.run_until_complete(
+        tasks._gather(*to_cancel, loop=loop, return_exceptions=True))
+
+    for task in to_cancel:
+        if task.cancelled():
+            continue
+        if task.exception() is not None:
+            loop.call_exception_handler({
+                'message': 'unhandled exception during asyncio.run() shutdown',
+                'exception': task.exception(),
+                'task': task,
+            })