Remove setHandler in NetworkStatsService

Currently, internal handler is set by setHandler after
constructing NSS object. This was introduced in ag/866187 to
access the handler in the unit test.

However, the design put NSS in a bad situation where all classes
that need handler or executor could not be final and need to be
dynamically allocated in order to get a valid handler.

Thus, since the usage of handler is removed in previous patch,
this change eliminate setHandler by initializing the handler in
the constructor.

Test: atest FrameworksNetTests
Bug: 150664039

Change-Id: I794a24d00b0ca9fdc78091e7b9ab7307e0f034b7

2 files changed, 64 insertions, 55 deletions

diff --git a/services/core/java/com/android/server/net/NetworkStatsService.java b/services/core/java/com/android/server/net/NetworkStatsService.java
index 896bf676d45b..66e691a79f97 100644
--- a/services/core/java/com/android/server/net/NetworkStatsService.java
+++ b/services/core/java/com/android/server/net/NetworkStatsService.java
@@ -306,9 +306,8 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
     /** Data layer operation counters for splicing into other structures. */
     private NetworkStats mUidOperations = new NetworkStats(0L, 10);
 
-    /** Must be set in factory by calling #setHandler. */
-    private Handler mHandler;
-    private Handler.Callback mHandlerCallback;
+    @NonNull
+    private final Handler mHandler;
 
     private volatile boolean mSystemReady;
     private long mPersistThreshold = 2 * MB_IN_BYTES;
@@ -324,6 +323,9 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
 
     private final static int DUMP_STATS_SESSION_COUNT = 20;
 
+    @NonNull
+    private final Dependencies mDeps;
+
     private static @NonNull File getDefaultSystemDir() {
         return new File(Environment.getDataDirectory(), "system");
     }
@@ -339,9 +341,24 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
                 Clock.systemUTC());
     }
 
-    private static final class NetworkStatsHandler extends Handler {
-        NetworkStatsHandler(Looper looper, Handler.Callback callback) {
-            super(looper, callback);
+    private final class NetworkStatsHandler extends Handler {
+        NetworkStatsHandler(@NonNull Looper looper) {
+            super(looper);
+        }
+
+        @Override
+        public void handleMessage(Message msg) {
+            switch (msg.what) {
+                case MSG_PERFORM_POLL: {
+                    performPoll(FLAG_PERSIST_ALL);
+                    break;
+                }
+                case MSG_PERFORM_POLL_REGISTER_ALERT: {
+                    performPoll(FLAG_PERSIST_NETWORK);
+                    registerGlobalAlert();
+                    break;
+                }
+            }
         }
     }
 
@@ -355,14 +372,10 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         NetworkStatsService service = new NetworkStatsService(context, networkManager, alarmManager,
                 wakeLock, getDefaultClock(), context.getSystemService(TelephonyManager.class),
                 new DefaultNetworkStatsSettings(context), new NetworkStatsFactory(),
-                new NetworkStatsObservers(), getDefaultSystemDir(), getDefaultBaseDir());
+                new NetworkStatsObservers(), getDefaultSystemDir(), getDefaultBaseDir(),
+                new Dependencies());
         service.registerLocalService();
 
-        HandlerThread handlerThread = new HandlerThread(TAG);
-        Handler.Callback callback = new HandlerCallback(service);
-        handlerThread.start();
-        Handler handler = new NetworkStatsHandler(handlerThread.getLooper(), callback);
-        service.setHandler(handler, callback);
         return service;
     }
 
@@ -373,7 +386,7 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
             AlarmManager alarmManager, PowerManager.WakeLock wakeLock, Clock clock,
             TelephonyManager teleManager, NetworkStatsSettings settings,
             NetworkStatsFactory factory, NetworkStatsObservers statsObservers, File systemDir,
-            File baseDir) {
+            File baseDir, @NonNull Dependencies deps) {
         mContext = Objects.requireNonNull(context, "missing Context");
         mNetworkManager = Objects.requireNonNull(networkManager,
             "missing INetworkManagementService");
@@ -387,6 +400,26 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         mSystemDir = Objects.requireNonNull(systemDir, "missing systemDir");
         mBaseDir = Objects.requireNonNull(baseDir, "missing baseDir");
         mUseBpfTrafficStats = new File("/sys/fs/bpf/map_netd_app_uid_stats_map").exists();
+        mDeps = Objects.requireNonNull(deps, "missing Dependencies");
+
+        final HandlerThread handlerThread = mDeps.makeHandlerThread();
+        handlerThread.start();
+        mHandler = new NetworkStatsHandler(handlerThread.getLooper());
+    }
+
+    /**
+     * Dependencies of NetworkStatsService, for injection in tests.
+     */
+    // TODO: Move more stuff into dependencies object.
+    @VisibleForTesting
+    public static class Dependencies {
+        /**
+         * Create a HandlerThread to use in NetworkStatsService.
+         */
+        @NonNull
+        public HandlerThread makeHandlerThread() {
+            return new HandlerThread(TAG);
+        }
     }
 
     private void registerLocalService() {
@@ -394,12 +427,6 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
                 new NetworkStatsManagerInternalImpl());
     }
 
-    @VisibleForTesting
-    void setHandler(Handler handler, Handler.Callback callback) {
-        mHandler = handler;
-        mHandlerCallback = callback;
-    }
-
     public void systemReady() {
         synchronized (mStatsLock) {
             mSystemReady = true;
@@ -1920,33 +1947,6 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
 
     }
 
-    @VisibleForTesting
-    static class HandlerCallback implements Handler.Callback {
-        private final NetworkStatsService mService;
-
-        HandlerCallback(NetworkStatsService service) {
-            this.mService = service;
-        }
-
-        @Override
-        public boolean handleMessage(Message msg) {
-            switch (msg.what) {
-                case MSG_PERFORM_POLL: {
-                    mService.performPoll(FLAG_PERSIST_ALL);
-                    return true;
-                }
-                case MSG_PERFORM_POLL_REGISTER_ALERT: {
-                    mService.performPoll(FLAG_PERSIST_NETWORK);
-                    mService.registerGlobalAlert();
-                    return true;
-                }
-                default: {
-                    return false;
-                }
-            }
-        }
-    }
-
     private void assertSystemReady() {
         if (!mSystemReady) {
             throw new IllegalStateException("System not ready");
diff --git a/tests/net/java/com/android/server/net/NetworkStatsServiceTest.java b/tests/net/java/com/android/server/net/NetworkStatsServiceTest.java
index 123b9c299f76..36deca3e37b7 100644
--- a/tests/net/java/com/android/server/net/NetworkStatsServiceTest.java
+++ b/tests/net/java/com/android/server/net/NetworkStatsServiceTest.java
@@ -64,6 +64,7 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import android.annotation.NonNull;
 import android.app.AlarmManager;
 import android.app.usage.NetworkStatsManager;
 import android.content.Context;
@@ -191,15 +192,11 @@ public class NetworkStatsServiceTest extends NetworkStatsBaseTest {
         PowerManager.WakeLock wakeLock =
                 powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
 
-        mService = new NetworkStatsService(
-                mServiceContext, mNetManager, mAlarmManager, wakeLock, mClock,
-                mServiceContext.getSystemService(TelephonyManager.class), mSettings,
-                mStatsFactory, new NetworkStatsObservers(),  mStatsDir, getBaseDir(mStatsDir));
         mHandlerThread = new HandlerThread("HandlerThread");
-        mHandlerThread.start();
-        Handler.Callback callback = new NetworkStatsService.HandlerCallback(mService);
-        final Handler handler = new Handler(mHandlerThread.getLooper(), callback);
-        mService.setHandler(handler, callback);
+        final NetworkStatsService.Dependencies deps = makeDependencies();
+        mService = new NetworkStatsService(mServiceContext, mNetManager, mAlarmManager, wakeLock,
+                mClock, mServiceContext.getSystemService(TelephonyManager.class), mSettings,
+                mStatsFactory, new NetworkStatsObservers(), mStatsDir, getBaseDir(mStatsDir), deps);
 
         mElapsedRealtime = 0L;
 
@@ -216,11 +213,21 @@ public class NetworkStatsServiceTest extends NetworkStatsBaseTest {
 
         // catch INetworkManagementEventObserver during systemReady()
         ArgumentCaptor<INetworkManagementEventObserver> networkObserver =
-              ArgumentCaptor.forClass(INetworkManagementEventObserver.class);
+                ArgumentCaptor.forClass(INetworkManagementEventObserver.class);
         verify(mNetManager).registerObserver(networkObserver.capture());
         mNetworkObserver = networkObserver.getValue();
     }
 
+    @NonNull
+    private NetworkStatsService.Dependencies makeDependencies() {
+        return new NetworkStatsService.Dependencies() {
+            @Override
+            public HandlerThread makeHandlerThread() {
+                return mHandlerThread;
+            }
+        };
+    }
+
     @After
     public void tearDown() throws Exception {
         IoUtils.deleteContents(mStatsDir);
@@ -233,6 +240,8 @@ public class NetworkStatsServiceTest extends NetworkStatsBaseTest {
 
         mSession.close();
         mService = null;
+
+        mHandlerThread.quitSafely();
     }
 
     @Test