AsyncioEventLoop: wrap child watcher for thread safety (bug 764905)
Use a child watcher wrapper to deliver the callbacks via the
call_soon_threadsafe method, since documentation for the asycio
AbstractChildWatcher class says that callbacks must be thread
safe.
Bug: https://bugs.gentoo.org/764905
Signed-off-by: Zac Medico <zmedico@gentoo.org>
diff --git a/lib/portage/util/_eventloop/asyncio_event_loop.py b/lib/portage/util/_eventloop/asyncio_event_loop.py
index 4d7047a..b777280 100644
--- a/lib/portage/util/_eventloop/asyncio_event_loop.py
+++ b/lib/portage/util/_eventloop/asyncio_event_loop.py
@@ -6,6 +6,7 @@
import asyncio as _real_asyncio
from asyncio.events import AbstractEventLoop as _AbstractEventLoop
+from asyncio.unix_events import AbstractChildWatcher as _AbstractChildWatcher
import portage
@@ -47,6 +48,7 @@
self.set_debug = loop.set_debug
self.get_debug = loop.get_debug
self._wakeup_fd = -1
+ self._child_watcher = None
if portage._internal_caller:
loop.set_exception_handler(self._internal_caller_exception_handler)
@@ -87,7 +89,9 @@
@rtype: asyncio.AbstractChildWatcher
@return: the internal event loop's AbstractChildWatcher interface
"""
- return _real_asyncio.get_child_watcher()
+ if self._child_watcher is None:
+ self._child_watcher = _ChildWatcherThreadSafetyWrapper(self, _real_asyncio.get_child_watcher())
+ return self._child_watcher
@property
def _asyncio_wrapper(self):
@@ -126,3 +130,27 @@
except ValueError:
# This is intended to fail when not called in the main thread.
pass
+
+
+class _ChildWatcherThreadSafetyWrapper(_AbstractChildWatcher):
+ def __init__(self, loop, real_watcher):
+ self._loop = loop
+ self._real_watcher = real_watcher
+
+ def close(self):
+ pass
+
+ def __enter__(self):
+ return self
+
+ def __exit__(self, a, b, c):
+ pass
+
+ def _child_exit(self, pid, status, callback, *args):
+ self._loop.call_soon_threadsafe(callback, pid, status, *args)
+
+ def add_child_handler(self, pid, callback, *args):
+ self._real_watcher.add_child_handler(pid, self._child_exit, callback, *args)
+
+ def remove_child_handler(self, pid):
+ return self._real_watcher.remove_child_handler(pid)
