Added SimpleTask.isAlive

app/src/debug/java/eu.faircode.email/CoalMine.java

@@ -71,6 +71,12 @@ public class CoalMine {
                                         reporter.getLabels().add("started=" + label);
                                     }
                                 }
+                                HeapField hfDestroyed = instance.get(className, "destroyed");
+                                if (hfDestroyed != null) {
+                                    Boolean destroyed = hfDestroyed.getValue().getAsBoolean();
+                                    if (destroyed != null)
+                                        reporter.getLabels().add("destroyed=" + destroyed);
+                                }
                             } else if (className.equals(TwoStateOwner.class.getName())) {
                                 HeapField hfState = instance.get(className, "state");
                                 if (hfState != null) {

app/src/main/java/eu/faircode/email/SimpleTask.java

@@ -49,10 +49,10 @@ import java.util.concurrent.Future;
 public abstract class SimpleTask<T> implements LifecycleObserver {
     private boolean log = true;
     private boolean count = true;
-    private boolean optional = false;
 
     private String name;
     private long started;
+    private boolean destroyed;
     private boolean reported;
     private Lifecycle.State state;
     private Future<?> future;
@@ -79,11 +79,6 @@ public abstract class SimpleTask<T> implements LifecycleObserver {
         return this;
     }
 
-    public SimpleTask<T> setOptional(boolean optional) {
-        this.optional = optional;
-        return this;
-    }
-
     public SimpleTask<T> setExecutor(ExecutorService executor) {
         this.localExecutor = executor;
         return this;
@@ -153,8 +148,7 @@ public abstract class SimpleTask<T> implements LifecycleObserver {
         LifecycleObserver watcher = new LifecycleObserver() {
             @OnLifecycleEvent(Lifecycle.Event.ON_DESTROY)
             public void onDestroy() {
-                EntityLog.log(context, EntityLog.Type.Debug, "Cancelling task=" + name);
+                destroyed = true;
-                cancel(context);
                 owner.getLifecycle().removeObserver(this);
             }
         };
@@ -197,8 +191,7 @@ public abstract class SimpleTask<T> implements LifecycleObserver {
                             // No delivery
                             cleanup(context);
                         } else {
-                            if (optional)
+                            owner.getLifecycle().removeObserver(watcher);
-                                owner.getLifecycle().removeObserver(watcher);
 
                             if (state.isAtLeast(Lifecycle.State.RESUMED)) {
                                 // Inline delivery
@@ -269,12 +262,15 @@ public abstract class SimpleTask<T> implements LifecycleObserver {
             }
         });
 
-        if (optional)
+        owner.getLifecycle().addObserver(watcher);
-            owner.getLifecycle().addObserver(watcher);
 
         updateTaskCount(context);
     }
 
+    public boolean isAlive() {
+        return !this.destroyed;
+    }
+
     void cancel(Context context) {
         if (future != null && future.cancel(false)) {
             Log.i("Cancelled task=" + name);

app/src/main/java/eu/faircode/email/ViewModelMessages.java

@@ -273,14 +273,6 @@ public class ViewModelMessages extends ViewModel {
             return;
         }
 
-        ObjectHolder<Boolean> alive = new ObjectHolder<>(true);
-        owner.getLifecycle().addObserver(new LifecycleObserver() {
-            @OnLifecycleEvent(Lifecycle.Event.ON_ANY)
-            public void onAny() {
-                alive.value = owner.getLifecycle().getCurrentState().isAtLeast(Lifecycle.State.STARTED);
-            }
-        });
-
         Log.i("Observe previous/next id=" + id);
         //model.list.getValue().loadAround(lpos);
         model.list.observe(owner, new Observer<PagedList<TupleMessageEx>>() {
@@ -354,6 +346,9 @@ public class ViewModelMessages extends ViewModel {
                         long id = args.getLong("id");
                         int lpos = args.getInt("lpos");
 
+                        if (!isAlive())
+                            return null;
+
                         PagedList<TupleMessageEx> plist = model.list.getValue();
                         if (plist == null)
                             return null;
@@ -372,7 +367,7 @@ public class ViewModelMessages extends ViewModel {
                                     return getPair(plist, ds, count, from + j);
                         }
 
-                        for (int i = 0; i < count && alive.value; i += CHUNK_SIZE) {
+                        for (int i = 0; i < count && isAlive(); i += CHUNK_SIZE) {
                             Log.i("Observe previous/next load" +
                                     " range=" + i + "/#" + count);
                             List<TupleMessageEx> messages = ds.loadRange(i, Math.min(CHUNK_SIZE, count - i));
@@ -431,7 +426,7 @@ public class ViewModelMessages extends ViewModel {
                         Log.i("Observe previous/next fallback=" + result);
                         return result;
                     }
-                }.setOptional(true).execute(context, owner, args, "model:fallback");
+                }.execute(context, owner, args, "model:fallback");
             }
         });
     }
@@ -449,13 +444,16 @@ public class ViewModelMessages extends ViewModel {
             protected List<Long> onExecute(Context context, Bundle args) {
                 List<Long> ids = new ArrayList<>();
 
+                if (!isAlive())
+                    return ids;
+
                 PagedList<TupleMessageEx> plist = model.list.getValue();
                 if (plist == null)
                     return ids;
 
                 LimitOffsetDataSource<TupleMessageEx> ds = (LimitOffsetDataSource<TupleMessageEx>) plist.getDataSource();
                 int count = ds.countItems();
-                for (int i = 0; i < count; i += 100)
+                for (int i = 0; i < count && isAlive(); i += 100)
                     for (TupleMessageEx message : ds.loadRange(i, Math.min(100, count - i)))
                         if ((message.uid != null && !message.folderReadOnly) ||
                                 message.accountProtocol != EntityAccount.TYPE_IMAP)