Enable strict mode for executors.

firebase-common/src/main/java/com/google/firebase/concurrent/CustomThreadFactory.java

@@ -14,26 +14,38 @@
 
 package com.google.firebase.concurrent;
 
+import android.os.Process;
+import android.os.StrictMode;
 import java.util.Locale;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.atomic.AtomicLong;
+import javax.annotation.Nullable;
 
 class CustomThreadFactory implements ThreadFactory {
   private static final ThreadFactory DEFAULT = Executors.defaultThreadFactory();
   private final AtomicLong threadCount = new AtomicLong();
   private final String namePrefix;
   private final int priority;
+  private final StrictMode.ThreadPolicy policy;
 
-  CustomThreadFactory(String namePrefix, int priority) {
+  CustomThreadFactory(String namePrefix, int priority, @Nullable StrictMode.ThreadPolicy policy) {
     this.namePrefix = namePrefix;
     this.priority = priority;
+    this.policy = policy;
   }
 
   @Override
   public Thread newThread(Runnable r) {
-    Thread thread = DEFAULT.newThread(r);
-    thread.setPriority(priority);
+    Thread thread =
+        DEFAULT.newThread(
+            () -> {
+              Process.setThreadPriority(priority);
+              if (policy != null) {
+                StrictMode.setThreadPolicy(policy);
+              }
+              r.run();
+            });
     thread.setName(
         String.format(Locale.ROOT, "%s Thread #%d", namePrefix, threadCount.getAndIncrement()));
     return thread;

firebase-common/src/main/java/com/google/firebase/concurrent/ExecutorsRegistrar.java

@@ -15,7 +15,10 @@
 package com.google.firebase.concurrent;
 
 import android.annotation.SuppressLint;
+import android.os.Build;
 import android.os.Process;
+import android.os.StrictMode;
+import com.google.firebase.BuildConfig;
 import com.google.firebase.annotations.concurrent.Background;
 import com.google.firebase.annotations.concurrent.Blocking;
 import com.google.firebase.annotations.concurrent.Lightweight;
@@ -40,15 +43,17 @@ public class ExecutorsRegistrar implements ComponentRegistrar {
           () ->
               scheduled(
                   Executors.newFixedThreadPool(
-                      4, factory("Firebase Background", Process.THREAD_PRIORITY_BACKGROUND))));
+                      4,
+                      factory(
+                          "Firebase Background", Process.THREAD_PRIORITY_BACKGROUND, bgPolicy()))));
 
   private static final Lazy<ScheduledExecutorService> LITE_EXECUTOR =
       new Lazy<>(
           () ->
               scheduled(
                   Executors.newFixedThreadPool(
                       Math.max(2, Runtime.getRuntime().availableProcessors()),
-                      factory("Firebase Lite", Process.THREAD_PRIORITY_DEFAULT))));
+                      factory("Firebase Lite", Process.THREAD_PRIORITY_DEFAULT, litePolicy()))));
 
   private static final Lazy<ScheduledExecutorService> BLOCKING_EXECUTOR =
       new Lazy<>(
@@ -97,6 +102,33 @@ private static ScheduledExecutorService scheduled(ExecutorService delegate) {
   }
 
   private static ThreadFactory factory(String threadPrefix, int priority) {
-    return new CustomThreadFactory(threadPrefix, priority);
+    return new CustomThreadFactory(threadPrefix, priority, null);
+  }
+
+  private static ThreadFactory factory(
+      String threadPrefix, int priority, StrictMode.ThreadPolicy policy) {
+    return new CustomThreadFactory(threadPrefix, priority, policy);
+  }
+
+  private static StrictMode.ThreadPolicy bgPolicy() {
+    StrictMode.ThreadPolicy.Builder builder = new StrictMode.ThreadPolicy.Builder().detectNetwork();
+    if (Build.VERSION.SDK_INT >= 23) {
+      builder.detectResourceMismatches();
+      if (Build.VERSION.SDK_INT >= 26) {
+        builder.detectUnbufferedIo();
+      }
+    }
+    if (BuildConfig.DEBUG) {
+      builder.penaltyDeath();
+    }
+    return builder.penaltyLog().build();
+  }
+
+  private static StrictMode.ThreadPolicy litePolicy() {
+    StrictMode.ThreadPolicy.Builder builder = new StrictMode.ThreadPolicy.Builder().detectAll();
+    if (BuildConfig.DEBUG) {
+      builder.penaltyDeath();
+    }
+    return builder.penaltyLog().build();
   }
 }