Add an observer to log blocked threads.

app/src/main/java/org/thoughtcrime/securesms/ApplicationContext.java

@@ -191,7 +191,7 @@ public class ApplicationContext extends MultiDexApplication implements AppForegr
     long startTime = System.currentTimeMillis();
     Log.i(TAG, "App is now visible.");
 
-    ApplicationDependencies.getFrameRateTracker().begin();
+    ApplicationDependencies.getFrameRateTracker().start();
     ApplicationDependencies.getMegaphoneRepository().onAppForegrounded();
 
     SignalExecutors.BOUNDED.execute(() -> {
@@ -203,6 +203,7 @@ public class ApplicationContext extends MultiDexApplication implements AppForegr
       KeyCachingService.onAppForegrounded(this);
       ApplicationDependencies.getShakeToReport().enable();
       checkBuildExpiration();
+      ApplicationDependencies.getDeadlockDetector().start();
     });
 
     Log.d(TAG, "onStart() took " + (System.currentTimeMillis() - startTime) + " ms");
@@ -213,8 +214,9 @@ public class ApplicationContext extends MultiDexApplication implements AppForegr
     Log.i(TAG, "App is no longer visible.");
     KeyCachingService.onAppBackgrounded(this);
     ApplicationDependencies.getMessageNotifier().clearVisibleThread();
-    ApplicationDependencies.getFrameRateTracker().end();
+    ApplicationDependencies.getFrameRateTracker().stop();
     ApplicationDependencies.getShakeToReport().disable();
+    ApplicationDependencies.getDeadlockDetector().stop();
   }
 
   public PersistentLogger getPersistentLogger() {

app/src/main/java/org/thoughtcrime/securesms/dependencies/ApplicationDependencies.java

@@ -5,6 +5,7 @@ import android.app.Application;
 import androidx.annotation.MainThread;
 import androidx.annotation.NonNull;
 
+import org.signal.core.util.concurrent.DeadlockDetector;
 import org.thoughtcrime.securesms.KbsEnclave;
 import org.thoughtcrime.securesms.components.TypingStatusRepository;
 import org.thoughtcrime.securesms.components.TypingStatusSender;
@@ -106,6 +107,7 @@ public class ApplicationDependencies {
   private static volatile SimpleExoPlayerPool          exoPlayerPool;
   private static volatile AudioManagerCompat           audioManagerCompat;
   private static volatile DonationsService             donationsService;
+  private static volatile DeadlockDetector             deadlockDetector;
 
   @MainThread
   public static void init(@NonNull Application application, @NonNull Provider provider) {
@@ -603,6 +605,17 @@ public class ApplicationDependencies {
     return donationsService;
   }
 
+  public static @NonNull DeadlockDetector getDeadlockDetector() {
+    if (deadlockDetector == null) {
+      synchronized (LOCK) {
+        if (deadlockDetector == null) {
+          deadlockDetector = provider.provideDeadlockDetector();
+        }
+      }
+    }
+    return deadlockDetector;
+  }
+
   public interface Provider {
     @NonNull GroupsV2Operations provideGroupsV2Operations();
     @NonNull SignalServiceAccountManager provideSignalServiceAccountManager();
@@ -639,5 +652,6 @@ public class ApplicationDependencies {
     @NonNull SimpleExoPlayerPool provideExoPlayerPool();
     @NonNull AudioManagerCompat provideAndroidCallAudioManager();
     @NonNull DonationsService provideDonationsService();
+    @NonNull DeadlockDetector provideDeadlockDetector();
   }
 }

app/src/main/java/org/thoughtcrime/securesms/dependencies/ApplicationDependencyProvider.java

@@ -2,9 +2,12 @@ package org.thoughtcrime.securesms.dependencies;
 
 import android.app.Application;
 import android.content.Context;
+import android.os.Handler;
+import android.os.HandlerThread;
 
 import androidx.annotation.NonNull;
 
+import org.signal.core.util.concurrent.DeadlockDetector;
 import org.signal.core.util.concurrent.SignalExecutors;
 import org.thoughtcrime.securesms.BuildConfig;
 import org.thoughtcrime.securesms.components.TypingStatusRepository;
@@ -76,6 +79,7 @@ import org.whispersystems.signalservice.api.websocket.WebSocketFactory;
 import org.whispersystems.signalservice.internal.websocket.WebSocketConnection;
 
 import java.util.UUID;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Implementation of {@link ApplicationDependencies.Provider} that provides real app dependencies.
@@ -311,6 +315,13 @@ public class ApplicationDependencyProvider implements ApplicationDependencies.Pr
                                 FeatureFlags.okHttpAutomaticRetry());
   }
 
+  @Override
+  public @NonNull DeadlockDetector provideDeadlockDetector() {
+    HandlerThread handlerThread = new HandlerThread("signal-DeadlockDetector");
+    handlerThread.start();
+    return new DeadlockDetector(new Handler(handlerThread.getLooper()), TimeUnit.SECONDS.toMillis(5));
+  }
+
   private @NonNull WebSocketFactory provideWebSocketFactory(@NonNull SignalWebSocketHealthMonitor healthMonitor) {
     return new WebSocketFactory() {
       @Override

app/src/main/java/org/thoughtcrime/securesms/util/FrameRateTracker.java

@@ -40,7 +40,7 @@ public class FrameRateTracker {
     updateRefreshRate();
   }
 
-  public void begin() {
+  public void start() {
     Log.d(TAG, String.format(Locale.ENGLISH, "Beginning frame rate tracking. Screen refresh rate: %.2f hz, or %.2f ms per frame.", refreshRate, idealTimePerFrameNanos / (float) 1_000_000));
 
     lastFrameTimeNanos  = System.nanoTime();
@@ -48,7 +48,7 @@ public class FrameRateTracker {
     Choreographer.getInstance().postFrameCallback(calculator);
   }
 
-  public void end() {
+  public void stop() {
     Choreographer.getInstance().removeFrameCallback(calculator);
   }