Session database: add count query.

libraries/session-storage/impl/src/main/kotlin/io/element/android/libraries/sessionstorage/impl/DatabaseSessionStore.kt

@@ -161,6 +161,15 @@ class DatabaseSessionStore(
         }
     }
 
+    override suspend fun numberOfSessions(): Int {
+        return sessionDataMutex.withLock {
+            database.sessionDataQueries.count()
+                .executeAsOneOrNull()
+                ?.toInt()
+                ?: 0
+        }
+    }
+
     override fun sessionsFlow(): Flow<List<SessionData>> {
         return database.sessionDataQueries.selectAll()
             .asFlow()

libraries/session-storage/impl/src/main/sqldelight/io/element/android/libraries/matrix/session/SessionData.sq

@@ -47,6 +47,9 @@ SELECT * FROM SessionData ORDER BY lastUsageIndex DESC LIMIT 1;
 selectAll:
 SELECT * FROM SessionData ORDER BY lastUsageIndex DESC;
 
+count:
+SELECT count(*) FROM SessionData;
+
 selectByUserId:
 SELECT * FROM SessionData WHERE userId = ?;