FairEmail/patches/room.patch

diff --git a/app/src/main/java/androidx/room/InvalidationTracker.java b/app/src/main/java/androidx/room/InvalidationTracker.java
index 99e69154b1..3a0c5ca530 100644
--- a/app/src/main/java/androidx/room/InvalidationTracker.java
+++ b/app/src/main/java/androidx/room/InvalidationTracker.java
@@ -464,8 +464,6 @@ public class InvalidationTracker {
                     final int tableId = cursor.getInt(0);
                     invalidatedTableIds.add(tableId);
                 }
-            } catch (Throwable ex) {
-                eu.faircode.email.Log.w(ex);
             } finally {
                 cursor.close();
             }
diff --git a/app/src/main/java/androidx/room/RoomTrackingLiveData.java b/app/src/main/java/androidx/room/RoomTrackingLiveData.java
index 10c4fbcf8b..8df1014a41 100644
--- a/app/src/main/java/androidx/room/RoomTrackingLiveData.java
+++ b/app/src/main/java/androidx/room/RoomTrackingLiveData.java
@@ -29,9 +29,6 @@ import java.util.Set;
 import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicInteger;
-
-import eu.faircode.email.EntityLog;
 
 /**
  * A LiveData implementation that closely works with {@link InvalidationTracker} to implement
@@ -62,8 +59,11 @@ class RoomTrackingLiveData<T> extends LiveData<T> {
     @SuppressWarnings("WeakerAccess")
     final InvalidationTracker.Observer mObserver;
 
-    final AtomicInteger queued = new AtomicInteger(0);
-    final AtomicInteger running = new AtomicInteger(0);
+    @SuppressWarnings("WeakerAccess")
+    final AtomicBoolean mInvalid = new AtomicBoolean(true);
+
+    @SuppressWarnings("WeakerAccess")
+    final AtomicBoolean mComputing = new AtomicBoolean(false);
 
     @SuppressWarnings("WeakerAccess")
     final AtomicBoolean mRegisteredObserver = new AtomicBoolean(false);
@@ -76,37 +76,39 @@ class RoomTrackingLiveData<T> extends LiveData<T> {
             if (mRegisteredObserver.compareAndSet(false, true)) {
                 mDatabase.getInvalidationTracker().addWeakObserver(mObserver);
             }
-            try {
-                running.incrementAndGet();
-
-                T value = null;
-                boolean computed = false;
-                synchronized (mComputeFunction) {
-                    int retry = 0;
-                    while (!computed) {
-                        try {
-                            value = mComputeFunction.call();
+            boolean computed;
+            do {
+                computed = false;
+                // compute can happen only in 1 thread but no reason to lock others.
+                if (mComputing.compareAndSet(false, true)) {
+                    // as long as it is invalid, keep computing.
+                    try {
+                        T value = null;
+                        while (mInvalid.compareAndSet(true, false)) {
                             computed = true;
-                        } catch (Throwable e) {
-                            if (++retry > 5) {
-                                eu.faircode.email.Log.e(e);
-                                break;
-                            }
-                            eu.faircode.email.Log.w(e);
                             try {
-                                Thread.sleep(2000L);
-                            } catch (InterruptedException ignored) {
+                                value = mComputeFunction.call();
+                            } catch (Exception e) {
+                                throw new RuntimeException("Exception while computing database"
+                                        + " live data.", e);
                             }
                         }
+                        if (computed) {
+                            postValue(value);
+                        }
+                    } finally {
+                        // release compute lock
+                        mComputing.set(false);
                     }
                 }
-                if (computed) {
-                    postValue(value);
-                }
-            } finally {
-                queued.decrementAndGet();
-                running.decrementAndGet();
-            }
+                // check invalid after releasing compute lock to avoid the following scenario.
+                // Thread A runs compute()
+                // Thread A checks invalid, it is false
+                // Main thread sets invalid to true
+                // Thread B runs, fails to acquire compute lock and skips
+                // Thread A releases compute lock
+                // We've left invalid in set state. The check below recovers.
+            } while (computed && mInvalid.get());
         }
     };
 
@@ -115,19 +117,14 @@ class RoomTrackingLiveData<T> extends LiveData<T> {
         @MainThread
         @Override
         public void run() {
-            if (running.get() == 0 && queued.get() > 0) {
-                eu.faircode.email.Log.persist(EntityLog.Type.Debug,
-                        mComputeFunction + " running=" + running + " queued=" + queued);
-                return;
-            }
             boolean isActive = hasActiveObservers();
-            if (isActive) {
-                queued.incrementAndGet();
-                getQueryExecutor().execute(mRefreshRunnable);
+            if (mInvalid.compareAndSet(false, true)) {
+                if (isActive) {
+                    getQueryExecutor().execute(mRefreshRunnable);
+                }
             }
         }
     };
-
     @SuppressLint("RestrictedApi")
     RoomTrackingLiveData(
             RoomDatabase database,