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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.car.hal;
     18 
     19 import android.car.hardware.CarSensorEvent;
     20 
     21 import com.android.car.vehiclenetwork.VehicleNetworkProto.VehiclePropConfig;
     22 import com.android.car.vehiclenetwork.VehicleNetworkProto.VehiclePropValue;
     23 
     24 import java.io.PrintWriter;
     25 import java.util.LinkedList;
     26 import java.util.List;
     27 
     28 /**
     29  * Common base for all SensorHal implementation.
     30  * It is wholly based on subscription and there is no explicit API for polling, but each sensor
     31  * should report its initial state immediately after {@link #requestSensorStart(int, int)} call.
     32  * It is ok to report sensor data {@link SensorListener#onSensorData(CarSensorEvent)} inside
     33  * the {@link #requestSensorStart(int, int)} call.
     34  */
     35 public abstract class SensorHalServiceBase  extends HalServiceBase {
     36     /**
     37      * Listener for monitoring sensor event. Only sensor service will implement this.
     38      */
     39     public interface SensorListener {
     40         /**
     41          * Sensor Hal is ready and is fully accessible.
     42          * This will be called after {@link SensorHalServiceBase#init()}.
     43          */
     44         void onSensorHalReady(SensorHalServiceBase hal);
     45         /**
     46          * Sensor events are available.
     47          * @param events
     48          */
     49         void onSensorEvents(List<CarSensorEvent> events);
     50     }
     51 
     52     private final LinkedList<CarSensorEvent> mDispatchQ = new LinkedList<CarSensorEvent>();
     53 
     54     public abstract void registerSensorListener(SensorListener listener);
     55 
     56     /**
     57      * Sensor HAL should be ready after init call.
     58      * @return
     59      */
     60     public abstract boolean isReady();
     61 
     62     /**
     63      * This should work after {@link #init()}.
     64      * @return
     65      */
     66     public abstract int[] getSupportedSensors();
     67 
     68     public abstract boolean requestSensorStart(int sensorType, int rate);
     69 
     70     public abstract void requestSensorStop(int sensorType);
     71 
     72     /**
     73      * Utility to help service to send one event as listener only takes list form.
     74      * @param listener
     75      * @param event
     76      */
     77     protected void dispatchCarSensorEvent(SensorListener listener, CarSensorEvent event) {
     78         synchronized (mDispatchQ) {
     79             mDispatchQ.add(event);
     80             listener.onSensorEvents(mDispatchQ);
     81             mDispatchQ.clear();
     82         }
     83     }
     84 
     85     @Override
     86     public void handleHalEvents(List<VehiclePropValue> values) {
     87         // default no-op impl. Necessary to not propagate this HAL specific event to logical
     88         // sensor provider.
     89         throw new RuntimeException("should not be called");
     90     }
     91 
     92     @Override
     93     public List<VehiclePropConfig> takeSupportedProperties(List<VehiclePropConfig> allProperties) {
     94         return null;
     95     }
     96 }
     97