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-rw-r--r--python/qemu/aqmp/util.py89
1 files changed, 89 insertions, 0 deletions
diff --git a/python/qemu/aqmp/util.py b/python/qemu/aqmp/util.py
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+"""
+Miscellaneous Utilities
+
+This module provides asyncio utilities and compatibility wrappers for
+Python 3.6 to provide some features that otherwise become available in
+Python 3.7+.
+"""
+
+import asyncio
+import sys
+from typing import (
+ Any,
+ Coroutine,
+ Optional,
+ TypeVar,
+)
+
+
+T = TypeVar('T')
+
+
+# -------------------------------
+# Section: Compatibility Wrappers
+# -------------------------------
+
+
+def create_task(coro: Coroutine[Any, Any, T],
+ loop: Optional[asyncio.AbstractEventLoop] = None
+ ) -> 'asyncio.Future[T]':
+ """
+ Python 3.6-compatible `asyncio.create_task` wrapper.
+
+ :param coro: The coroutine to execute in a task.
+ :param loop: Optionally, the loop to create the task in.
+
+ :return: An `asyncio.Future` object.
+ """
+ if sys.version_info >= (3, 7):
+ if loop is not None:
+ return loop.create_task(coro)
+ return asyncio.create_task(coro) # pylint: disable=no-member
+
+ # Python 3.6:
+ return asyncio.ensure_future(coro, loop=loop)
+
+
+def is_closing(writer: asyncio.StreamWriter) -> bool:
+ """
+ Python 3.6-compatible `asyncio.StreamWriter.is_closing` wrapper.
+
+ :param writer: The `asyncio.StreamWriter` object.
+ :return: `True` if the writer is closing, or closed.
+ """
+ if sys.version_info >= (3, 7):
+ return writer.is_closing()
+
+ # Python 3.6:
+ transport = writer.transport
+ assert isinstance(transport, asyncio.WriteTransport)
+ return transport.is_closing()
+
+
+async def wait_closed(writer: asyncio.StreamWriter) -> None:
+ """
+ Python 3.6-compatible `asyncio.StreamWriter.wait_closed` wrapper.
+
+ :param writer: The `asyncio.StreamWriter` to wait on.
+ """
+ if sys.version_info >= (3, 7):
+ await writer.wait_closed()
+ return
+
+ # Python 3.6
+ transport = writer.transport
+ assert isinstance(transport, asyncio.WriteTransport)
+
+ while not transport.is_closing():
+ await asyncio.sleep(0)
+
+ # This is an ugly workaround, but it's the best I can come up with.
+ sock = transport.get_extra_info('socket')
+
+ if sock is None:
+ # Our transport doesn't have a socket? ...
+ # Nothing we can reasonably do.
+ return
+
+ while sock.fileno() != -1:
+ await asyncio.sleep(0)