Evgeny @ SimpleX Chat
1.1 KiB
Simplex.Messaging.Server.NtfStore
In-memory notification store: per-notifier message notification lists with expiration.
Source: NtfStore.hs
storeNtf — outside-STM lookup with STM fallback
storeNtf uses TM.lookupIO outside STM, then falls back to TM.lookup inside STM if the notifier entry doesn't exist. This is the same outside-STM lookup pattern used in Server.hs and Client/Agent.hs — avoids transaction re-evaluation from unrelated map changes. The double-check inside STM prevents races when two messages arrive concurrently for a new notifier.
deleteExpiredNtfs — last-is-earliest optimization
Notifications are prepended (cons), so the last element in the list is the earliest. deleteExpiredNtfs checks last ntfs first — if the earliest notification is not expired, none are, and the entire list is skipped without filtering. This avoids traversing notification lists that have no expired entries.
The outer readTVarIO check for empty list avoids entering an STM transaction at all for notifiers with no notifications.