content: /*
   * Copyright (C) 2016 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;
  
  import android.content.BroadcastReceiver;
  import android.content.Context;
  import android.content.Intent;
  import android.content.IntentFilter;
  import android.hardware.GeomagneticField;
  import android.hardware.Sensor;
  import android.hardware.SensorAdditionalInfo;
  import android.hardware.SensorEvent;
  import android.hardware.SensorEventListener;
  import android.hardware.SensorManager;
  import android.location.Location;
  import android.location.LocationListener;
  import android.location.LocationManager;
  import android.os.Bundle;
  import android.os.SystemClock;
  import android.os.SystemProperties;
  import android.os.UserHandle;
  import android.provider.Settings;
  import android.util.Slog;
  
  public class SensorNotificationService extends SystemService
          implements SensorEventListener, LocationListener {
      private static final boolean DBG = false;
      private static final String TAG = "SensorNotificationService";
  
      private static final long MINUTE_IN_MS = 60 * 1000;
      private static final long KM_IN_M = 1000;
  
      private static final long LOCATION_MIN_TIME = 30 * MINUTE_IN_MS;
      private static final long LOCATION_MIN_DISTANCE = 100 * KM_IN_M;
  
      private static final String PROPERTY_USE_MOCKED_LOCATION =
              "sensor.notification.use_mocked"; // max key length is 32
  
      private static final long MILLIS_2010_1_1 = 1262358000000l;
  
      private Context mContext;
      private SensorManager mSensorManager;
      private LocationManager mLocationManager;
      private Sensor mMetaSensor;
  
      // for rate limiting
      private long mLocalGeomagneticFieldUpdateTime = -LOCATION_MIN_TIME;
  
      public SensorNotificationService(Context context) {
          super(context);
          mContext = context;
      }
  
      public void onStart() {
          LocalServices.addService(SensorNotificationService.class, this);
      }
  
      public void onBootPhase(int phase) {
          if (phase == PHASE_THIRD_PARTY_APPS_CAN_START) {
              mSensorManager = (SensorManager) mContext.getSystemService(Context.SENSOR_SERVICE);
              mMetaSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_DYNAMIC_SENSOR_META);
              if (mMetaSensor == null) {
                  if (DBG) Slog.d(TAG, "Cannot obtain dynamic meta sensor, not supported.");
              } else {
                  mSensorManager.registerListener(this, mMetaSensor,
                          SensorManager.SENSOR_DELAY_FASTEST);
              }
          }
  
          if (phase == PHASE_BOOT_COMPLETED) {
              // LocationManagerService is initialized after PHASE_THIRD_PARTY_APPS_CAN_START
              mLocationManager =
                      (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
              if (mLocationManager == null) {
                  if (DBG) Slog.d(TAG, "Cannot obtain location service.");
              } else {
                  mLocationManager.requestLocationUpdates(
                          LocationManager.PASSIVE_PROVIDER,
                          LOCATION_MIN_TIME,
                          LOCATION_MIN_DISTANCE,
                          this);
              }
          }
      }
  
      private void broadcastDynamicSensorChanged() {
          Intent i = new Intent(Intent.ACTION_DYNAMIC_SENSOR_CHANGED);
          i.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY); // avoid waking up manifest receivers
          mContext.sendBroadcastAsUser(i, UserHandle.ALL);
          if (DBG) Slog.d(TAG, "dynamic sensor broadcast sent");
      }
  
      @Override
      public void onSensorChanged(SensorEvent event) {
          if (event.sensor == mMetaSensor) {
              broadcastDynamicSensorChanged();
          }
      }
  
      @Override
      public void onLocationChanged(Location location) {
          if (DBG) Slog.d(TAG, String.format(
                  "Location is (%f, %f), h %f, acc %f, mocked %b",
                  location.getLatitude(), location.getLongitude(),
                  location.getAltitude(), location.getAccuracy(),
                  location.isFromMockProvider()));
  
          // lat long == 0 usually means invalid location
          if (location.getLatitude() == 0 && location.getLongitude() == 0) {
              return;
          }
  
          // update too often, ignore
          if (SystemClock.elapsedRealtime() - mLocalGeomagneticFieldUpdateTime < 10 * MINUTE_IN_MS) {
              return;
          }
  
          long time = System.currentTimeMillis();
          // Mocked location should not be used. Except in test, only use mocked location
          // Wrong system clock also gives bad values so ignore as well.
          if (useMockedLocation() == location.isFromMockProvider() || time < MILLIS_2010_1_1) {
              return;
          }
  
          GeomagneticField field = new GeomagneticField(
                  (float) location.getLatitude(), (float) location.getLongitude(),
                  (float) location.getAltitude(), time);
          if (DBG) Slog.d(TAG, String.format(
                  "Nominal mag field, norm %fuT, decline %f deg, incline %f deg",
                  field.getFieldStrength() / 1000, field.getDeclination(), field.getInclination()));
  
          try {
              SensorAdditionalInfo info = SensorAdditionalInfo.createLocalGeomagneticField(
                          field.getFieldStrength() / 1000, // convert from nT to uT
                          (float)(field.getDeclination() * Math.PI / 180), // from degree to rad
                          (float)(field.getInclination() * Math.PI / 180)); // from degree to rad
              if (info != null) {
                  mSensorManager.setOperationParameter(info);
                  mLocalGeomagneticFieldUpdateTime = SystemClock.elapsedRealtime();
              }
          } catch (IllegalArgumentException e) {
              Slog.e(TAG, "Invalid local geomagnetic field, ignore.");
          }
      }
  
      @Override
      public void onAccuracyChanged(Sensor sensor, int accuracy) {}
      @Override
      public void onStatusChanged(String provider, int status, Bundle extras) {}
      @Override
      public void onProviderEnabled(String provider) {}
      @Override
      public void onProviderDisabled(String provider) {}
  
      private boolean useMockedLocation() {
          return "false".equals(System.getProperty(PROPERTY_USE_MOCKED_LOCATION, "false"));
      }
  }
  
  