Block in RestStrategy until PushDecryptJobs finish.

src/org/thoughtcrime/securesms/IncomingMessageProcessor.java

@@ -3,6 +3,7 @@ package org.thoughtcrime.securesms;
 import android.content.Context;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
 import org.thoughtcrime.securesms.database.Address;
 import org.thoughtcrime.securesms.database.DatabaseFactory;
@@ -74,7 +75,11 @@ public class IncomingMessageProcessor {
       this.jobManager        = ApplicationDependencies.getJobManager();
     }
 
-    public void processEnvelope(@NonNull SignalServiceEnvelope envelope) {
+    /**
+     * @return The id of the {@link PushDecryptJob} that was scheduled to process the message, if
+     *         one was created. Otherwise null.
+     */
+    public @Nullable String processEnvelope(@NonNull SignalServiceEnvelope envelope) {
       if (envelope.hasSource()) {
         Recipient recipient = Recipient.external(context, envelope.getSource());
 
@@ -86,17 +91,24 @@ public class IncomingMessageProcessor {
 
       if (envelope.isReceipt()) {
         processReceipt(envelope);
+        return null;
       } else if (envelope.isPreKeySignalMessage() || envelope.isSignalMessage() || envelope.isUnidentifiedSender()) {
-        processMessage(envelope);
+        return processMessage(envelope);
       } else {
         Log.w(TAG, "Received envelope of unknown type: " + envelope.getType());
+        return null;
       }
     }
 
-    private void processMessage(@NonNull SignalServiceEnvelope envelope) {
+    private @NonNull String processMessage(@NonNull SignalServiceEnvelope envelope) {
       Log.i(TAG, "Received message. Inserting in PushDatabase.");
-      long id = pushDatabase.insert(envelope);
-      jobManager.add(new PushDecryptJob(context, id));
+
+      long           id  = pushDatabase.insert(envelope);
+      PushDecryptJob job = new PushDecryptJob(context, id);
+
+      jobManager.add(job);
+
+      return job.getId();
     }
 
     private void processReceipt(@NonNull SignalServiceEnvelope envelope) {

src/org/thoughtcrime/securesms/gcm/RestStrategy.java

@@ -2,14 +2,21 @@ package org.thoughtcrime.securesms.gcm;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.WorkerThread;
+import androidx.lifecycle.Observer;
 
 import org.thoughtcrime.securesms.IncomingMessageProcessor;
 import org.thoughtcrime.securesms.dependencies.ApplicationDependencies;
+import org.thoughtcrime.securesms.jobmanager.JobTracker;
 import org.thoughtcrime.securesms.logging.Log;
 import org.whispersystems.signalservice.api.SignalServiceMessageReceiver;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * Retrieves messages over the REST endpoint.
@@ -26,15 +33,29 @@ public class RestStrategy implements MessageRetriever.Strategy {
     long startTime = System.currentTimeMillis();
 
     try (IncomingMessageProcessor.Processor processor = ApplicationDependencies.getIncomingMessageProcessor().acquire()) {
-      SignalServiceMessageReceiver receiver = ApplicationDependencies.getSignalServiceMessageReceiver();
+      SignalServiceMessageReceiver receiver  = ApplicationDependencies.getSignalServiceMessageReceiver();
+      AtomicReference<String>      lastJobId = new AtomicReference<>(null);
+      AtomicInteger                jobCount  = new AtomicInteger(0);
+
       receiver.setSoTimeoutMillis(SOCKET_TIMEOUT);
 
       receiver.retrieveMessages(envelope -> {
         Log.i(TAG, "Retrieved an envelope." + timeSuffix(startTime));
-        processor.processEnvelope(envelope);
+        String jobId = processor.processEnvelope(envelope);
+
+        if (jobId != null) {
+          lastJobId.set(jobId);
+          jobCount.incrementAndGet();
+        }
         Log.i(TAG, "Successfully processed an envelope." + timeSuffix(startTime));
       });
 
+      Log.d(TAG, jobCount.get() + " PushDecryptJob(s) were enqueued.");
+
+      if (lastJobId.get() != null) {
+        blockUntilJobIsFinished(lastJobId.get());
+      }
+
       return true;
     } catch (IOException e) {
       Log.w(TAG, "Failed to retrieve messages. Resetting the SignalServiceMessageReceiver.", e);
@@ -42,6 +63,30 @@ public class RestStrategy implements MessageRetriever.Strategy {
       return false;
     }
   }
+  private static void blockUntilJobIsFinished(@NonNull String jobId) {
+    long           startTime = System.currentTimeMillis();
+    CountDownLatch latch     = new CountDownLatch(1);
+
+    ApplicationDependencies.getJobManager().addListener(jobId, new JobTracker.JobListener() {
+      @Override
+      public void onStateChanged(@NonNull JobTracker.JobState jobState) {
+        if (jobState.isComplete()) {
+          ApplicationDependencies.getJobManager().removeListener(this);
+          latch.countDown();
+        }
+      }
+    });
+
+    try {
+      if (!latch.await(10, TimeUnit.SECONDS)) {
+        Log.w(TAG, "Timed out waiting for PushDecryptJob(s) to finish!");
+      }
+    } catch (InterruptedException e) {
+      throw new AssertionError(e);
+    }
+
+    Log.d(TAG, "Waited " + (System.currentTimeMillis() - startTime) + " ms for the PushDecryptJob(s) to finish.");
+  }
 
   private static String timeSuffix(long startTime) {
     return " (" + (System.currentTimeMillis() - startTime) + " ms elapsed)";

src/org/thoughtcrime/securesms/jobmanager/Job.java

@@ -40,7 +40,7 @@ public abstract class Job {
     this.parameters = parameters;
   }
 
-  public final String getId() {
+  public final @NonNull String getId() {
     return parameters.getId();
   }
 
@@ -254,7 +254,7 @@ public abstract class Job {
       return queue;
     }
 
-    List<String> getConstraintKeys() {
+    @NonNull List<String> getConstraintKeys() {
       return constraintKeys;
     }