portdbapi._event_loop: split out _safe_loop function

Signed-off-by: Zac Medico <zmedico@gentoo.org>

2 files changed, 19 insertions, 9 deletions

diff --git a/lib/portage/dbapi/porttree.py b/lib/portage/dbapi/porttree.py
index 7a28f5876..edff0c2f2 100644
--- a/lib/portage/dbapi/porttree.py
+++ b/lib/portage/dbapi/porttree.py
@@ -34,7 +34,6 @@ from portage import eclass_cache, \
 from portage import os
 from portage import _encodings
 from portage import _unicode_encode
-from portage.util._eventloop.EventLoop import EventLoop
 from portage.util.futures import asyncio
 from portage.util.futures.compat_coroutine import coroutine, coroutine_return
 from portage.util.futures.iter_completed import iter_gather
@@ -346,14 +345,7 @@ class portdbapi(dbapi):
 
 	@property
 	def _event_loop(self):
-		if portage._internal_caller:
-			# For internal portage usage, asyncio._wrap_loop() is safe.
-			return asyncio._wrap_loop()
-		else:
-			# For external API consumers, use a local EventLoop, since
-			# we don't want to assume that it's safe to override the
-			# global SIGCHLD handler.
-			return EventLoop(main=False)
+		return asyncio._safe_loop()
 
 	def _create_pregen_cache(self, tree):
 		conf = self.repositories.get_repo_for_location(tree)
diff --git a/lib/portage/util/futures/_asyncio/__init__.py b/lib/portage/util/futures/_asyncio/__init__.py
index 2a637624d..e77c7a690 100644
--- a/lib/portage/util/futures/_asyncio/__init__.py
+++ b/lib/portage/util/futures/_asyncio/__init__.py
@@ -37,6 +37,7 @@ import portage
 portage.proxy.lazyimport.lazyimport(globals(),
 	'portage.util.futures.unix_events:_PortageEventLoopPolicy',
 	'portage.util.futures:compat_coroutine@_compat_coroutine',
+	'portage.util._eventloop.EventLoop:EventLoop@_EventLoop',
 )
 from portage.util._eventloop.asyncio_event_loop import AsyncioEventLoop as _AsyncioEventLoop
 from portage.util._eventloop.global_event_loop import (
@@ -250,3 +251,20 @@ if _asyncio_enabled:
 		loop = loop or _global_event_loop()
 		return (loop if hasattr(loop, '_asyncio_wrapper')
 			else _AsyncioEventLoop(loop=loop))
+
+
+def _safe_loop():
+	"""
+	Return an event loop that's safe to use within the current context.
+	For portage internal callers, this returns a globally shared event
+	loop instance. For external API consumers, this constructs a
+	temporary event loop instance that's safe to use in a non-main
+	thread (it does not override the global SIGCHLD handler).
+
+	@rtype: asyncio.AbstractEventLoop (or compatible)
+	@return: event loop instance
+	"""
+	if portage._internal_caller:
+		return _wrap_loop()
+	else:
+		return _EventLoop(main=False)