From 84f20f6646832755e8406381d05d757e22a645cb Mon Sep 17 00:00:00 2001
From: Vincent Breitmoser <look@my.amazin.horse>
Date: Fri, 13 Jul 2018 14:52:50 +0200
Subject: [PATCH] synchronously schedule background work, to avoid cancelling
 race condition

---
 .../keychain/KeychainApplication.java         |  2 +-
 .../keysync/KeyserverSyncManager.java         | 23 +++++++++++++++----
 .../keychain/ui/SettingsActivity.java         |  2 +-
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/KeychainApplication.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/KeychainApplication.java
index 3cd3353ea..b51071e3e 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/KeychainApplication.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/KeychainApplication.java
@@ -102,7 +102,7 @@ public class KeychainApplication extends Application {
         TlsCertificatePinning.addPinnedCertificate("api.keybase.io", getAssets(), "api.keybase.io.CA.cer");
         TlsCertificatePinning.addPinnedCertificate("keyserver.ubuntu.com", getAssets(), "DigiCertGlobalRootCA.cer");
 
-        KeyserverSyncManager.updateKeyserverSyncSchedule(this, Constants.DEBUG_KEYSERVER_SYNC);
+        KeyserverSyncManager.updateKeyserverSyncScheduleAsync(this, Constants.DEBUG_KEYSERVER_SYNC);
 
         TemporaryFileProvider.scheduleCleanupImmediately();
     }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/keysync/KeyserverSyncManager.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/keysync/KeyserverSyncManager.java
index 228a50518..8ce36ff9e 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/keysync/KeyserverSyncManager.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/keysync/KeyserverSyncManager.java
@@ -21,6 +21,7 @@ package org.sufficientlysecure.keychain.keysync;
 import java.util.concurrent.TimeUnit;
 
 import android.content.Context;
+import android.os.AsyncTask;
 import android.os.Build.VERSION;
 import android.os.Build.VERSION_CODES;
 
@@ -28,6 +29,7 @@ import androidx.work.Constraints.Builder;
 import androidx.work.NetworkType;
 import androidx.work.OneTimeWorkRequest;
 import androidx.work.PeriodicWorkRequest;
+import androidx.work.SynchronousWorkManager;
 import androidx.work.WorkManager;
 import org.sufficientlysecure.keychain.util.Preferences;
 import timber.log.Timber;
@@ -39,17 +41,30 @@ public class KeyserverSyncManager {
 
     private static final String PERIODIC_WORK_TAG = "keyserverSync";
 
-    public static void updateKeyserverSyncSchedule(Context context, boolean forceReschedule) {
+    public static void updateKeyserverSyncScheduleAsync(Context context, boolean forceReschedule) {
         Preferences prefs = Preferences.getPreferences(context);
         if (!forceReschedule && prefs.isKeyserverSyncScheduled() != prefs.isKeyserverSyncEnabled()) {
             return;
         }
-        WorkManager workManager = WorkManager.getInstance();
+
+        new AsyncTask<Void,Void,Void>() {
+            @Override
+            protected Void doInBackground(Void... voids) {
+                updateKeyserverSyncSchedule(context, forceReschedule);
+                return null;
+            }
+        }.execute();
+    }
+
+    private static void updateKeyserverSyncSchedule(Context context, boolean forceReschedule) {
+        Preferences prefs = Preferences.getPreferences(context);
+        // for some reason, the task is not actually scheduled sometimes unless we  use the synchronous interface.
+        SynchronousWorkManager workManager = WorkManager.getInstance().synchronous();
         if (workManager == null) {
             Timber.e("WorkManager unavailable!");
             return;
         }
-        workManager.cancelAllWorkByTag(PERIODIC_WORK_TAG);
+        workManager.cancelAllWorkByTagSync(PERIODIC_WORK_TAG);
 
         if (!prefs.isKeyserverSyncEnabled()) {
             return;
@@ -67,7 +82,7 @@ public class KeyserverSyncManager {
                         .setConstraints(constraints.build())
                         .addTag(PERIODIC_WORK_TAG)
                         .build();
-        workManager.enqueue(workRequest);
+        workManager.enqueueSync(workRequest);
 
         prefs.setKeyserverSyncScheduled(true);
     }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/SettingsActivity.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/SettingsActivity.java
index 46b5f3a7d..f12943f14 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/SettingsActivity.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/SettingsActivity.java
@@ -415,7 +415,7 @@ public class SettingsActivity extends AppCompatPreferenceActivity {
         @Override
         public void onStop() {
             super.onStop();
-            KeyserverSyncManager.updateKeyserverSyncSchedule(getActivity(), true);
+            KeyserverSyncManager.updateKeyserverSyncScheduleAsync(getActivity(), true);
         }
 
         @Override