ios, core: better notifications processing to avoid contention for database (#3485)

* core: forward notifications about message processing (for iOS notifications)

* simplexmq

* the option to keep database key, to allow re-opening the database

* export new init with keepKey and reopen DB api

* stop remote ctrl when suspending chat

* ios: close/re-open db on suspend/activate

* allow activating chat without restoring (for NSE)

* update NSE to suspend/activate (does not work)

* simplexmq

* suspend chat and close database when last notification in the process is processed

* stop reading notifications on message markers

* replace async stream with cancellable concurrent queue

* better synchronization of app and NSE

* remove outside of task

* remove unused var

* whitespace

* more debug logging, handle cancelled read after dequeue

* comments

* more comments

apps/ios/SimpleXChat/API.swift

@@ -41,7 +41,7 @@ public func chatMigrateInit(_ useKey: String? = nil, confirmMigrations: Migratio
     var cKey = dbKey.cString(using: .utf8)!
     var cConfirm = confirm.rawValue.cString(using: .utf8)!
     // the last parameter of chat_migrate_init is used to return the pointer to chat controller
-    let cjson = chat_migrate_init(&cPath, &cKey, &cConfirm, &chatController)!
+    let cjson = chat_migrate_init_key(&cPath, &cKey, 1, &cConfirm, &chatController)!
     let dbRes = dbMigrationResult(fromCString(cjson))
     let encrypted = dbKey != ""
     let keychainErr = dbRes == .ok && useKeychain && encrypted && !kcDatabasePassword.set(dbKey)
@@ -57,6 +57,13 @@ public func chatCloseStore() {
     }
 }
 
+public func chatReopenStore() {
+    let err = fromCString(chat_reopen_store(getChatCtrl()))
+    if err != "" {
+        logger.error("chatReopenStore error: \(err)")
+    }
+}
+
 public func resetChatCtrl() {
     chatController = nil
     migrationResult = nil