content: /*
   * Copyright (C) 2018 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License
   */
  
  package com.android.server.wm;
  
  import android.content.Intent;
  import android.os.Handler;
  import android.os.Looper;
  import android.os.Message;
  
  import com.android.internal.os.BackgroundThread;
  import com.android.internal.util.function.pooled.PooledLambda;
  
  import java.util.ArrayList;
  
  /**
   * Multi-cast implementation of {@link ActivityMetricsLaunchObserver}.
   *
   * <br /><br />
   * If this class is called through the {@link ActivityMetricsLaunchObserver} interface,
   * then the call is forwarded to all registered observers at the time.
   *
   * <br /><br />
   * All calls are invoked asynchronously in-order on a background thread. This fulfills the
   * sequential ordering guarantee in {@link ActivityMetricsLaunchObserverRegistry}.
   *
   * @see ActivityTaskManagerInternal#getLaunchObserverRegistry()
   */
  class LaunchObserverRegistryImpl implements
          ActivityMetricsLaunchObserverRegistry, ActivityMetricsLaunchObserver {
      private final ArrayList<ActivityMetricsLaunchObserver> mList = new ArrayList<>();
  
      /**
       * All calls are posted to a handler because:
       *
       * 1. We don't know how long the observer will take to handle this call and we don't want
       *    to block the WM critical section on it.
       * 2. We don't know the lock ordering of the observer so we don't want to expose a chance
       *    of deadlock.
       */
      private final Handler mHandler;
  
      public LaunchObserverRegistryImpl(Looper looper) {
          mHandler = new Handler(looper);
      }
  
      @Override
      public void registerLaunchObserver(ActivityMetricsLaunchObserver launchObserver) {
          mHandler.sendMessage(PooledLambda.obtainMessage(
                  LaunchObserverRegistryImpl::handleRegisterLaunchObserver, this, launchObserver));
      }
  
      @Override
      public void unregisterLaunchObserver(ActivityMetricsLaunchObserver launchObserver) {
          mHandler.sendMessage(PooledLambda.obtainMessage(
                  LaunchObserverRegistryImpl::handleUnregisterLaunchObserver, this, launchObserver));
      }
  
      @Override
      public void onIntentStarted(Intent intent) {
          mHandler.sendMessage(PooledLambda.obtainMessage(
                  LaunchObserverRegistryImpl::handleOnIntentStarted, this, intent));
      }
  
      @Override
      public void onIntentFailed() {
          mHandler.sendMessage(PooledLambda.obtainMessage(
                  LaunchObserverRegistryImpl::handleOnIntentFailed, this));
      }
  
      @Override
      public void onActivityLaunched(
              @ActivityRecordProto byte[] activity,
              int temperature) {
          mHandler.sendMessage(PooledLambda.obtainMessage(
                  LaunchObserverRegistryImpl::handleOnActivityLaunched,
                  this, activity, temperature));
      }
  
      @Override
      public void onActivityLaunchCancelled(
          @ActivityRecordProto byte[] activity) {
          mHandler.sendMessage(PooledLambda.obtainMessage(
                  LaunchObserverRegistryImpl::handleOnActivityLaunchCancelled, this, activity));
      }
  
      @Override
      public void onActivityLaunchFinished(
          @ActivityRecordProto byte[] activity) {
          mHandler.sendMessage(PooledLambda.obtainMessage(
                  LaunchObserverRegistryImpl::handleOnActivityLaunchFinished, this, activity));
      }
  
      // Use PooledLambda.obtainMessage to invoke below methods. Every method reference must be
      // unbound (i.e. not capture any variables explicitly or implicitly) to fulfill the
      // singleton-lambda requirement.
  
      private void handleRegisterLaunchObserver(ActivityMetricsLaunchObserver observer) {
          mList.add(observer);
      }
  
      private void handleUnregisterLaunchObserver(ActivityMetricsLaunchObserver observer) {
          mList.remove(observer);
      }
  
      private void handleOnIntentStarted(Intent intent) {
          // Traverse start-to-end to meet the registerLaunchObserver multi-cast order guarantee.
          for (int i = 0; i < mList.size(); i++) {
               ActivityMetricsLaunchObserver o = mList.get(i);
               o.onIntentStarted(intent);
          }
      }
  
      private void handleOnIntentFailed() {
          // Traverse start-to-end to meet the registerLaunchObserver multi-cast order guarantee.
          for (int i = 0; i < mList.size(); i++) {
               ActivityMetricsLaunchObserver o = mList.get(i);
               o.onIntentFailed();
          }
      }
  
      private void handleOnActivityLaunched(
              @ActivityRecordProto byte[] activity,
              @Temperature int temperature) {
          // Traverse start-to-end to meet the registerLaunchObserver multi-cast order guarantee.
          for (int i = 0; i < mList.size(); i++) {
               ActivityMetricsLaunchObserver o = mList.get(i);
               o.onActivityLaunched(activity, temperature);
          }
      }
  
      private void handleOnActivityLaunchCancelled(
              @ActivityRecordProto byte[] activity) {
          // Traverse start-to-end to meet the registerLaunchObserver multi-cast order guarantee.
          for (int i = 0; i < mList.size(); i++) {
               ActivityMetricsLaunchObserver o = mList.get(i);
               o.onActivityLaunchCancelled(activity);
          }
      }
  
      private void handleOnActivityLaunchFinished(
              @ActivityRecordProto byte[] activity) {
          // Traverse start-to-end to meet the registerLaunchObserver multi-cast order guarantee.
          for (int i = 0; i < mList.size(); i++) {
              ActivityMetricsLaunchObserver o = mList.get(i);
              o.onActivityLaunchFinished(activity);
          }
      }
  }
  