David Turner 44ba9ab04d
Fix racy use of ConcurrentHashMap (#36603)
ConcurrentHashMap does not always behave correctly if removing elements and
concurrently checking for its emptyiness. Work around this by protecting all
usages with a mutex (there was only one usage unprotected by the mutex anyway)
and then we don't even need a ConcurrentHashMap at all.
2018-12-14 12:15:42 +00:00
..