ios: close store when app is about to terminate

apps/ios/Shared/Model/SuspendChat.swift

@@ -45,7 +45,10 @@ func suspendBgRefresh() {
     }
 }
 
+private var terminating = false
+
 func terminateChat() {
+    terminating = true
     suspendLockQueue.sync {
         switch appStateGroupDefault.get() {
         case .suspending:
@@ -73,6 +76,9 @@ private func _chatSuspended() {
     if ChatModel.shared.chatRunning == true {
         ChatReceiver.shared.stop()
     }
+    if terminating {
+        chatCloseStore()
+    }
 }
 
 func activateChat(appState: AppState = .active) {

apps/ios/SimpleXChat/API.swift

@@ -50,6 +50,13 @@ public func chatMigrateInit(_ useKey: String? = nil, confirmMigrations: Migratio
     return result
 }
 
+public func chatCloseStore() {
+    let err = fromCString(chat_close_store(getChatCtrl()))
+    if err != "" {
+        logger.error("chatCloseStore error: \(err)")
+    }
+}
+
 public func resetChatCtrl() {
     chatController = nil
     migrationResult = nil

apps/ios/SimpleXChat/SimpleX.h

@@ -17,6 +17,8 @@ typedef void* chat_ctrl;
 
 // the last parameter is used to return the pointer to chat controller
 extern char *chat_migrate_init(char *path, char *key, char *confirm, chat_ctrl *ctrl);
+extern char *chat_close_store(chat_ctrl ctl)
+extern char *chat_open_store(chat_ctrl ctl, char *key);
 extern char *chat_send_cmd(chat_ctrl ctl, char *cmd);
 extern char *chat_recv_msg(chat_ctrl ctl);
 extern char *chat_recv_msg_wait(chat_ctrl ctl, int wait);