diff --git a/synapse/util/async_helpers.py b/synapse/util/async_helpers.py
index f1c46836b1..804dbca443 100644
--- a/synapse/util/async_helpers.py
+++ b/synapse/util/async_helpers.py
@@ -13,12 +13,16 @@
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
+
import collections
import logging
from contextlib import contextmanager
+from typing import Dict, Sequence, Set, Union
from six.moves import range
+import attr
+
from twisted.internet import defer
from twisted.internet.defer import CancelledError
from twisted.python import failure
@@ -213,7 +217,9 @@ class Linearizer(object):
# the first element is the number of things executing, and
# the second element is an OrderedDict, where the keys are deferreds for the
# things blocked from executing.
- self.key_to_defer = {}
+ self.key_to_defer = (
+ {}
+ ) # type: Dict[str, Sequence[Union[int, Dict[defer.Deferred, int]]]]
def queue(self, key):
# we avoid doing defer.inlineCallbacks here, so that cancellation works correctly.
@@ -340,10 +346,10 @@ class ReadWriteLock(object):
def __init__(self):
# Latest readers queued
- self.key_to_current_readers = {}
+ self.key_to_current_readers = {} # type: Dict[str, Set[defer.Deferred]]
# Latest writer queued
- self.key_to_current_writer = {}
+ self.key_to_current_writer = {} # type: Dict[str, defer.Deferred]
@defer.inlineCallbacks
def read(self, key):
@@ -479,3 +485,30 @@ def timeout_deferred(deferred, timeout, reactor, on_timeout_cancel=None):
deferred.addCallbacks(success_cb, failure_cb)
return new_d
+
+
+@attr.s(slots=True, frozen=True)
+class DoneAwaitable(object):
+ """Simple awaitable that returns the provided value.
+ """
+
+ value = attr.ib()
+
+ def __await__(self):
+ return self
+
+ def __iter__(self):
+ return self
+
+ def __next__(self):
+ raise StopIteration(self.value)
+
+
+def maybe_awaitable(value):
+ """Convert a value to an awaitable if not already an awaitable.
+ """
+
+ if hasattr(value, "__await__"):
+ return value
+
+ return DoneAwaitable(value)
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