wait until dispatched jobs are done

deltachat · May 13, 2021 · 73db6a1 · 73db6a1
1 parent d355b60
commit 73db6a1
Showing 1 changed file with 18 additions and 3 deletions.
diff --git a/deltachat-ios/AppDelegate.swift b/deltachat-ios/AppDelegate.swift
@@ -202,9 +202,15 @@ class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterD
             } else if app.backgroundTimeRemaining < 10 {
                 logger.info("⬅️ few background time, \(app.backgroundTimeRemaining), stopping")
                 self.dcContext.stopIo()
-                DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
+
+                // to avoid 0xdead10cc exceptions, scheduled jobs need to be done before we get suspended;
+                // we increase the probabilty that this happens by adding unregisterBackgroundTask()
+                // to the end of both dispatch queues.
+                DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
                     logger.info("⬅️ few background time, \(app.backgroundTimeRemaining), done")
-                    self.unregisterBackgroundTask()
+                    DispatchQueue.global(qos: .background).async {
+                        self.unregisterBackgroundTask()
+                    }
                 }
             } else {
                 logger.info("⬅️ remaining background time: \(app.backgroundTimeRemaining)")
@@ -382,7 +388,16 @@ class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterD
             if !self.appIsInForeground() {
                 self.dcContext.stopIo()
             }
-            completionHandler(.newData)
+
+            // to avoid 0xdead10cc exceptions, scheduled jobs need to be done before we get suspended;
+            // we increase the probabilty that this happens by adding completionHandler()
+            // to the end of both dispatch queues.  
+            DispatchQueue.main.asyncAfter(deadline: .now() + 1) {
+                logger.info("⬅️ fetch finished")
+                DispatchQueue.global(qos: .background).async {
+                    completionHandler(.newData)
+                }
+            }
         }
     }