service/src/com/android/car/CarPropertyService.java - platform/packages/services/Car - Git at Google

 /*
  * 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.car;

 import static java.lang.Integer.toHexString;

 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.car.Car;
 import android.car.hardware.CarPropertyConfig;
 import android.car.hardware.CarPropertyValue;
 import android.car.hardware.property.CarPropertyEvent;
 import android.car.hardware.property.ICarProperty;
 import android.car.hardware.property.ICarPropertyEventListener;
 import android.content.Context;
 import android.os.Handler;
 import android.os.HandlerThread;
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.util.ArrayMap;
 import android.util.IndentingPrintWriter;
 import android.util.Pair;
 import android.util.Slog;
 import android.util.SparseArray;

 import com.android.car.hal.PropertyHalService;
 import com.android.internal.annotations.GuardedBy;
 import com.android.server.utils.Slogf;

 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;

 /**
  * This class implements the binder interface for ICarProperty.aidl to make it easier to create
  * multiple managers that deal with Vehicle Properties. The property Ids in this class are IDs in
  * manager level.
  */
 public class CarPropertyService extends ICarProperty.Stub
         implements CarServiceBase, PropertyHalService.PropertyHalListener {
     private static final boolean DBG = true;
     private static final String TAG = CarLog.tagFor(CarPropertyService.class);
     private final Context mContext;
     private final PropertyHalService mHal;
     private final Object mLock = new Object();
     @GuardedBy("mLock")
     private final Map<IBinder, Client> mClientMap = new ArrayMap<>();
     @GuardedBy("mLock")
     private final SparseArray<List<Client>> mPropIdClientMap = new SparseArray<>();
     @GuardedBy("mLock")
     private final SparseArray<SparseArray<Client>> mSetOperationClientMap = new SparseArray<>();
     private final HandlerThread mHandlerThread =
             CarServiceUtils.getHandlerThread(getClass().getSimpleName());
     private final Handler mHandler = new Handler(mHandlerThread.getLooper());
     // Use SparseArray instead of map to save memory.
     @GuardedBy("mLock")
     private SparseArray<CarPropertyConfig<?>> mConfigs = new SparseArray<>();
     @GuardedBy("mLock")
     private SparseArray<Pair<String, String>> mPropToPermission = new SparseArray<>();

     public CarPropertyService(Context context, PropertyHalService hal) {
         if (DBG) {
             Slog.d(TAG, "CarPropertyService started!");
         }
         mHal = hal;
         mContext = context;
     }

     // Helper class to keep track of listeners to this service.
     private class Client implements IBinder.DeathRecipient {
         private final ICarPropertyEventListener mListener;
         private final IBinder mListenerBinder;
         private final Object mLock = new Object();
         // propId->rate map.
         @GuardedBy("mLock")
         private final SparseArray<Float> mRateMap = new SparseArray<Float>();
         @GuardedBy("mLock")
         private boolean mIsDead = false;

         Client(ICarPropertyEventListener listener) {
             mListener = listener;
             mListenerBinder = listener.asBinder();

             try {
                 mListenerBinder.linkToDeath(this, 0);
             } catch (RemoteException e) {
                 mIsDead = true;
             }
         }

         /**
          * Returns whether this client is already dead.
          *
          * Caller should not assume this client is alive after getting True response because the
          * binder might die after this function checks the status. Caller should only use this
          * function to fail early.
          */
         boolean isDead() {
             synchronized (mLock) {
                 return mIsDead;
             }
         }

         void addProperty(int propId, float rate) {
             synchronized (mLock) {
                 if (mIsDead) {
                     return;
                 }
                 mRateMap.put(propId, rate);
             }
         }

         float getRate(int propId) {
             synchronized (mLock) {
                 // Return 0 if no key found, since that is the slowest rate.
                 return mRateMap.get(propId, 0.0f);
             }
         }

         int removeProperty(int propId) {
             synchronized (mLock) {
                 mRateMap.remove(propId);
                 return mRateMap.size();
             }
         }

         /**
          * Handler to be called when client died.
          *
          * Remove the listener from HAL service and unregister if this is the last client.
          */
         @Override
         public void binderDied() {
             List<Integer> propIds = new ArrayList<>();
             synchronized (mLock) {
                 mIsDead = true;

                 if (DBG) {
                     Slogf.d(TAG, "binderDied %s", mListenerBinder);
                 }

                 // Because we set mIsDead to true here, we are sure mRateMap would not have new
                 // elements. The propIds here is going to cover all the prop Ids that we need to
                 // unregister.
                 for (int i = 0; i < mRateMap.size(); i++) {
                     propIds.add(mRateMap.keyAt(i));
                 }
             }

             CarPropertyService.this.unregisterListenerBinderForProps(propIds, mListenerBinder);
         }

         /**
          * Calls onEvent function on the listener if the binder is alive.
          *
          * There is still chance when onEvent might fail because binderDied is not called before
          * this function.
          */
         void onEvent(List<CarPropertyEvent> events) throws RemoteException {
             synchronized (mLock) {
                 if (mIsDead) {
                     return;
                 }
             }
             mListener.onEvent(events);
         }
     }

     @Override
     public void init() {
         synchronized (mLock) {
             // Cache the configs list and permissions to avoid subsequent binder calls
             mConfigs = mHal.getPropertyList();
             mPropToPermission = mHal.getPermissionsForAllProperties();
         }
         if (DBG) {
             Slog.d(TAG, "cache CarPropertyConfigs " + mConfigs.size());
         }
         mHal.setListener(this);
     }

     @Override
     public void release() {
         synchronized (mLock) {
             mClientMap.clear();
             mPropIdClientMap.clear();
             mHal.setListener(null);
             mSetOperationClientMap.clear();
         }
     }

     @Override
     public void dump(IndentingPrintWriter writer) {
         writer.println("*CarPropertyService*");
         writer.increaseIndent();
         synchronized (mLock) {
             writer.println(String.format("There are %d clients using CarPropertyService.",
                     mClientMap.size()));
             writer.println("Properties registered: ");
             writer.increaseIndent();
             for (int i = 0; i < mPropIdClientMap.size(); i++) {
                 int propId = mPropIdClientMap.keyAt(i);
                 writer.println("propId: 0x" + toHexString(propId)
                         + " is registered by " + mPropIdClientMap.valueAt(i).size()
                         + " client(s).");
             }
             writer.decreaseIndent();
             writer.println("Properties changed by CarPropertyService: ");
             writer.increaseIndent();
             for (int i = 0; i < mSetOperationClientMap.size(); i++) {
                 int propId = mSetOperationClientMap.keyAt(i);
                 SparseArray areaIdToClient = mSetOperationClientMap.valueAt(i);
                 for (int j = 0; j < areaIdToClient.size(); j++) {
                     int areaId = areaIdToClient.keyAt(j);
                     writer.println(String.format("propId: 0x%s areaId: 0x%s by client: %s",
                             toHexString(propId), toHexString(areaId), areaIdToClient.valueAt(j)));
                 }
             }
             writer.decreaseIndent();
         }
         writer.decreaseIndent();
     }

     @Override
     public void registerListener(int propId, float rate, ICarPropertyEventListener listener) {
         if (DBG) {
             Slog.d(TAG, "registerListener: propId=0x" + toHexString(propId) + " rate=" + rate);
         }
         if (listener == null) {
             Slog.e(TAG, "registerListener: Listener is null.");
             throw new IllegalArgumentException("listener cannot be null.");
         }

         IBinder listenerBinder = listener.asBinder();
         CarPropertyConfig propertyConfig;
         Client finalClient;
         synchronized (mLock) {
             propertyConfig = mConfigs.get(propId);
             if (propertyConfig == null) {
                 // Do not attempt to register an invalid propId
                 Slog.e(TAG, "registerListener:  propId is not in config list: 0x" + toHexString(
                         propId));
                 return;
             }
             ICarImpl.assertPermission(mContext, mHal.getReadPermission(propId));
             // Get or create the client for this listener
             Client client = mClientMap.get(listenerBinder);
             if (client == null) {
                 client = new Client(listener);
                 if (client.isDead()) {
                     Slogf.w(TAG, "the ICarPropertyEventListener is already dead");
                     return;
                 }
                 mClientMap.put(listenerBinder, client);
             }
             client.addProperty(propId, rate);
             // Insert the client into the propId --> clients map
             List<Client> clients = mPropIdClientMap.get(propId);
             if (clients == null) {
                 clients = new ArrayList<Client>();
                 mPropIdClientMap.put(propId, clients);
             }
             if (!clients.contains(client)) {
                 clients.add(client);
             }
             // Set the new rate
             if (rate > mHal.getSampleRate(propId)) {
                 mHal.subscribeProperty(propId, rate);
             }
             finalClient = client;
         }

         // propertyConfig and client are NonNull.
         mHandler.post(() ->
                 getAndDispatchPropertyInitValue(propertyConfig, finalClient));
     }

     private void getAndDispatchPropertyInitValue(CarPropertyConfig config, Client client) {
         List<CarPropertyEvent> events = new ArrayList<>();
         int propId = config.getPropertyId();
         if (config.isGlobalProperty()) {
             CarPropertyValue value = mHal.getPropertySafe(propId, 0);
             if (value != null) {
                 CarPropertyEvent event = new CarPropertyEvent(
                         CarPropertyEvent.PROPERTY_EVENT_PROPERTY_CHANGE, value);
                 events.add(event);
             }
         } else {
             for (int areaId : config.getAreaIds()) {
                 CarPropertyValue value = mHal.getPropertySafe(propId, areaId);
                 if (value != null) {
                     CarPropertyEvent event = new CarPropertyEvent(
                             CarPropertyEvent.PROPERTY_EVENT_PROPERTY_CHANGE, value);
                     events.add(event);
                 }
             }
         }
         try {
             client.onEvent(events);
         } catch (RemoteException ex) {
             // If we cannot send a record, its likely the connection snapped. Let the binder
             // death handle the situation.
             Slogf.e(TAG, "onEvent calling failed", ex);
         }
     }

     @Override
     public void unregisterListener(int propId, ICarPropertyEventListener listener) {
         if (DBG) {
             Slog.d(TAG, "unregisterListener propId=0x" + toHexString(propId));
         }
         ICarImpl.assertPermission(mContext, mHal.getReadPermission(propId));
         if (listener == null) {
             Slog.e(TAG, "unregisterListener: Listener is null.");
             throw new IllegalArgumentException("Listener is null");
         }

         IBinder listenerBinder = listener.asBinder();
         unregisterListenerBinderForProps(List.of(propId), listenerBinder);
     }

     @GuardedBy("mLock")
     private void unregisterListenerBinderLocked(int propId, IBinder listenerBinder) {
         float updateMaxRate = 0f;
         Client client = mClientMap.get(listenerBinder);
         List<Client> propertyClients = mPropIdClientMap.get(propId);
         if (mConfigs.get(propId) == null) {
             // Do not attempt to unregister an invalid propId
             Slogf.e(TAG, "unregisterListener: propId is not in config list:0x%s",
                     toHexString(propId));
             return;
         }
         if ((client == null) || (propertyClients == null)) {
             Slogf.e(TAG, "unregisterListenerBinderLocked: Listener was not previously "
                     + "registered.");
         } else {
             if (propertyClients.remove(client)) {
                 int propLeft = client.removeProperty(propId);
                 if (propLeft == 0) {
                     mClientMap.remove(listenerBinder);
                 }
                 clearSetOperationRecorderLocked(propId, client);

             } else {
                 Slogf.e(TAG, "unregisterListenerBinderLocked: Listener was not registered for "
                         + "propId=0x" + toHexString(propId));
             }

             if (propertyClients.isEmpty()) {
                 // Last listener for this property unsubscribed.  Clean up
                 mPropIdClientMap.remove(propId);
                 mSetOperationClientMap.remove(propId);
             } else {
                 // Other listeners are still subscribed.  Calculate the new rate
                 for (int i = 0; i < propertyClients.size(); i++) {
                     Client c = propertyClients.get(i);
                     float rate = c.getRate(propId);
                     updateMaxRate = Math.max(rate, updateMaxRate);
                 }
             }
         }
         if (Float.compare(updateMaxRate, 0f) == 0) {
             // Unsubscribe property if we did not find any other client register to this property
             mHal.unsubscribeProperty(propId);
         } else if (Float.compare(updateMaxRate, mHal.getSampleRate(propId)) != 0) {
             try {
                 // Only reset the sample rate if needed
                 mHal.subscribeProperty(propId, updateMaxRate);
             } catch (IllegalArgumentException e) {
                 Slogf.e(TAG, "failed to subscribe to propId=0x" + toHexString(propId)
                         + ", error: " + e);
             }
         }
     }

     private void unregisterListenerBinderForProps(List<Integer> propIds, IBinder listenerBinder) {
         synchronized (mLock) {
             for (int i = 0; i < propIds.size(); i++) {
                 int propId = propIds.get(i);
                 unregisterListenerBinderLocked(propId, listenerBinder);
             }
         }
     }

     /**
      * Return the list of properties' configs that the caller may access.
      */
     @NonNull
     @Override
     public List<CarPropertyConfig> getPropertyList() {
         int[] allPropId;
         // Avoid permission checking under lock.
         synchronized (mLock) {
             allPropId = new int[mConfigs.size()];
             for (int i = 0; i < mConfigs.size(); i++) {
                 allPropId[i] = mConfigs.keyAt(i);
             }
         }
         return getPropertyConfigList(allPropId);
     }

     /**
      *
      * @param propIds Array of property Ids
      * @return the list of properties' configs that the caller may access.
      */
     @NonNull
     @Override
     public List<CarPropertyConfig> getPropertyConfigList(int[] propIds) {
         // Cache the granted permissions
         Set<String> grantedPermission = new HashSet<>();
         List<CarPropertyConfig> availableProp = new ArrayList<>();
         if (propIds == null) {
             return availableProp;
         }
         for (int propId : propIds) {
             String readPermission = getReadPermission(propId);
             if (readPermission == null) {
                 continue;
             }
             // Check if context already granted permission first
             if (grantedPermission.contains(readPermission)
                     || ICarImpl.hasPermission(mContext, readPermission)) {
                 grantedPermission.add(readPermission);
                 synchronized (mLock) {
                     availableProp.add(mConfigs.get(propId));
                 }
             }
         }
         if (DBG) {
             Slog.d(TAG, "getPropertyList returns " + availableProp.size() + " configs");
         }
         return availableProp;
     }

     @Override
     public CarPropertyValue getProperty(int prop, int zone) {
         synchronized (mLock) {
             if (mConfigs.get(prop) == null) {
                 // Do not attempt to register an invalid propId
                 Slog.e(TAG, "getProperty: propId is not in config list:0x" + toHexString(prop));
                 return null;
             }
         }
         ICarImpl.assertPermission(mContext, mHal.getReadPermission(prop));
         return mHal.getProperty(prop, zone);
     }

     /**
      * Get property value for car service's internal usage.
      * @param prop property id
      * @param zone area id
      * @return null if property is not implemented or there is an exception in the vehicle.
      */
     public CarPropertyValue getPropertySafe(int prop, int zone) {
         synchronized (mLock) {
             if (mConfigs.get(prop) == null) {
                 // Do not attempt to register an invalid propId
                 Slog.e(TAG, "getPropertySafe: propId is not in config list:0x"
                         + toHexString(prop));
                 return null;
             }
         }
         ICarImpl.assertPermission(mContext, mHal.getReadPermission(prop));
         return mHal.getPropertySafe(prop, zone);
     }

     @Nullable
     @Override
     public String getReadPermission(int propId) {
         Pair<String, String> permissions;
         synchronized (mLock) {
             permissions = mPropToPermission.get(propId);
         }
         if (permissions == null) {
             // Property ID does not exist
             Slog.e(TAG,
                     "getReadPermission: propId is not in config list:0x" + toHexString(propId));
             return null;
         }
         return permissions.first;
     }

     @Nullable
     @Override
     public String getWritePermission(int propId) {
         Pair<String, String> permissions;
         synchronized (mLock) {
             permissions = mPropToPermission.get(propId);
         }
         if (permissions == null) {
             // Property ID does not exist
             Slog.e(TAG,
                     "getWritePermission: propId is not in config list:0x" + toHexString(propId));
             return null;
         }
         return permissions.second;
     }

     @Override
     public void setProperty(CarPropertyValue prop, ICarPropertyEventListener listener) {
         int propId = prop.getPropertyId();
         checkPropertyAccessibility(propId);
         // need an extra permission for writing display units properties.
         if (mHal.isDisplayUnitsProperty(propId)) {
             ICarImpl.assertPermission(mContext, Car.PERMISSION_VENDOR_EXTENSION);
         }
         mHal.setProperty(prop);
         IBinder listenerBinder = listener.asBinder();
         synchronized (mLock) {
             Client client = mClientMap.get(listenerBinder);
             if (client == null) {
                 client = new Client(listener);
             }
             if (client.isDead()) {
                 Slogf.w(TAG, "the ICarPropertyEventListener is already dead");
                 return;
             }
             updateSetOperationRecorderLocked(propId, prop.getAreaId(), client);
         }
     }

     // The helper method checks if the vehicle has implemented this property and the property
     // is accessible or not for platform and client.
     private void checkPropertyAccessibility(int propId) {
         // Checks if the car implemented the property or not.
         synchronized (mLock) {
             if (mConfigs.get(propId) == null) {
                 throw new IllegalArgumentException("Property Id: 0x" + Integer.toHexString(propId)
                         + " does not exist in the vehicle");
             }
         }

         // Checks if android has permission to write property.
         String propertyWritePermission = mHal.getWritePermission(propId);
         if (propertyWritePermission == null) {
             throw new SecurityException("Platform does not have permission to change value for "
                     + "property Id: 0x" + Integer.toHexString(propId));
         }
         // Checks if the client has the permission.
         ICarImpl.assertPermission(mContext, propertyWritePermission);
     }

      // Updates recorder for set operation.
     @GuardedBy("mLock")
     private void updateSetOperationRecorderLocked(int propId, int areaId, Client client) {
         if (mSetOperationClientMap.get(propId) != null) {
             mSetOperationClientMap.get(propId).put(areaId, client);
         } else {
             SparseArray<Client> areaIdToClient = new SparseArray<>();
             areaIdToClient.put(areaId, client);
             mSetOperationClientMap.put(propId, areaIdToClient);
         }
     }

     // Clears map when client unregister for property.
     private void clearSetOperationRecorderLocked(int propId, Client client) {
         SparseArray<Client> areaIdToClient = mSetOperationClientMap.get(propId);
         if (areaIdToClient != null) {
             List<Integer> indexNeedToRemove = new ArrayList<>();
             for (int index = 0; index < areaIdToClient.size(); index++) {
                 if (client.equals(areaIdToClient.valueAt(index))) {
                     indexNeedToRemove.add(index);
                 }
             }

             for (int index : indexNeedToRemove) {
                 if (DBG) {
                     Slog.d("ErrorEvent", " Clear propId:0x" + toHexString(propId)
                             + " areaId: 0x" + toHexString(areaIdToClient.keyAt(index)));
                 }
                 areaIdToClient.removeAt(index);
             }
         }
     }

     // Implement PropertyHalListener interface
     @Override
     public void onPropertyChange(List<CarPropertyEvent> events) {
         Map<Client, List<CarPropertyEvent>> eventsToDispatch = new ArrayMap<>();

         synchronized (mLock) {
             for (int i = 0; i < events.size(); i++) {
                 CarPropertyEvent event = events.get(i);
                 int propId = event.getCarPropertyValue().getPropertyId();
                 List<Client> clients = mPropIdClientMap.get(propId);
                 if (clients == null) {
                     Slogf.e(TAG, "onPropertyChange: no listener registered for propId=0x%s",
                             toHexString(propId));
                     continue;
                 }

                 for (int j = 0; j < clients.size(); j++) {
                     Client c = clients.get(j);
                     List<CarPropertyEvent> p = eventsToDispatch.get(c);
                     if (p == null) {
                         // Initialize the linked list for the listener
                         p = new ArrayList<CarPropertyEvent>();
                         eventsToDispatch.put(c, p);
                     }
                     p.add(event);
                 }
             }

             // Parse the dispatch list to send events
             for (Client client : eventsToDispatch.keySet()) {
                 try {
                     client.onEvent(eventsToDispatch.get(client));
                 } catch (RemoteException ex) {
                     // If we cannot send a record, its likely the connection snapped. Let binder
                     // death handle the situation.
                     Slogf.e(TAG, "onEvent calling failed",  ex);
                 }
             }
         }
     }

     @Override
     public void onPropertySetError(int property, int areaId, int errorCode) {
         Client lastOperatedClient = null;
         synchronized (mLock) {
             if (mSetOperationClientMap.get(property) != null
                     && mSetOperationClientMap.get(property).get(areaId) != null) {
                 lastOperatedClient = mSetOperationClientMap.get(property).get(areaId);
             } else {
                 Slog.e(TAG, "Can not find the client changed propertyId: 0x"
                         + toHexString(property) + " in areaId: 0x" + toHexString(areaId));
             }

         }
         if (lastOperatedClient != null) {
             dispatchToLastClient(property, areaId, errorCode, lastOperatedClient);
         }
     }

     private void dispatchToLastClient(int property, int areaId, int errorCode,
             Client lastOperatedClient) {
         try {
             List<CarPropertyEvent> eventList = new ArrayList<>();
             eventList.add(
                     CarPropertyEvent.createErrorEventWithErrorCode(property, areaId,
                             errorCode));
             lastOperatedClient.onEvent(eventList);
         } catch (RemoteException ex) {
             Slogf.e(TAG, "onEvent calling failed", ex);
         }
     }
 }
	/*
	* 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.car;

	import static java.lang.Integer.toHexString;

	import android.annotation.NonNull;
	import android.annotation.Nullable;
	import android.car.Car;
	import android.car.hardware.CarPropertyConfig;
	import android.car.hardware.CarPropertyValue;
	import android.car.hardware.property.CarPropertyEvent;
	import android.car.hardware.property.ICarProperty;
	import android.car.hardware.property.ICarPropertyEventListener;
	import android.content.Context;
	import android.os.Handler;
	import android.os.HandlerThread;
	import android.os.IBinder;
	import android.os.RemoteException;
	import android.util.ArrayMap;
	import android.util.IndentingPrintWriter;
	import android.util.Pair;
	import android.util.Slog;
	import android.util.SparseArray;

	import com.android.car.hal.PropertyHalService;
	import com.android.internal.annotations.GuardedBy;
	import com.android.server.utils.Slogf;

	import java.util.ArrayList;
	import java.util.HashSet;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;

	/**
	* This class implements the binder interface for ICarProperty.aidl to make it easier to create
	* multiple managers that deal with Vehicle Properties. The property Ids in this class are IDs in
	* manager level.
	*/
	public class CarPropertyService extends ICarProperty.Stub
	implements CarServiceBase, PropertyHalService.PropertyHalListener {
	private static final boolean DBG = true;
	private static final String TAG = CarLog.tagFor(CarPropertyService.class);
	private final Context mContext;
	private final PropertyHalService mHal;
	private final Object mLock = new Object();
	@GuardedBy("mLock")
	private final Map<IBinder, Client> mClientMap = new ArrayMap<>();
	@GuardedBy("mLock")
	private final SparseArray<List<Client>> mPropIdClientMap = new SparseArray<>();
	@GuardedBy("mLock")
	private final SparseArray<SparseArray<Client>> mSetOperationClientMap = new SparseArray<>();
	private final HandlerThread mHandlerThread =
	CarServiceUtils.getHandlerThread(getClass().getSimpleName());
	private final Handler mHandler = new Handler(mHandlerThread.getLooper());
	// Use SparseArray instead of map to save memory.
	@GuardedBy("mLock")
	private SparseArray<CarPropertyConfig<?>> mConfigs = new SparseArray<>();
	@GuardedBy("mLock")
	private SparseArray<Pair<String, String>> mPropToPermission = new SparseArray<>();

	public CarPropertyService(Context context, PropertyHalService hal) {
	if (DBG) {
	Slog.d(TAG, "CarPropertyService started!");
	}
	mHal = hal;
	mContext = context;
	}

	// Helper class to keep track of listeners to this service.
	private class Client implements IBinder.DeathRecipient {
	private final ICarPropertyEventListener mListener;
	private final IBinder mListenerBinder;
	private final Object mLock = new Object();
	// propId->rate map.
	@GuardedBy("mLock")
	private final SparseArray<Float> mRateMap = new SparseArray<Float>();
	@GuardedBy("mLock")
	private boolean mIsDead = false;

	Client(ICarPropertyEventListener listener) {
	mListener = listener;
	mListenerBinder = listener.asBinder();

	try {
	mListenerBinder.linkToDeath(this, 0);
	} catch (RemoteException e) {
	mIsDead = true;
	}
	}

	/**
	* Returns whether this client is already dead.
	*
	* Caller should not assume this client is alive after getting True response because the
	* binder might die after this function checks the status. Caller should only use this
	* function to fail early.
	*/
	boolean isDead() {
	synchronized (mLock) {
	return mIsDead;
	}
	}

	void addProperty(int propId, float rate) {
	synchronized (mLock) {
	if (mIsDead) {
	return;
	}
	mRateMap.put(propId, rate);
	}
	}

	float getRate(int propId) {
	synchronized (mLock) {
	// Return 0 if no key found, since that is the slowest rate.
	return mRateMap.get(propId, 0.0f);
	}
	}

	int removeProperty(int propId) {
	synchronized (mLock) {
	mRateMap.remove(propId);
	return mRateMap.size();
	}
	}

	/**
	* Handler to be called when client died.
	*
	* Remove the listener from HAL service and unregister if this is the last client.
	*/
	@Override
	public void binderDied() {
	List<Integer> propIds = new ArrayList<>();
	synchronized (mLock) {
	mIsDead = true;

	if (DBG) {
	Slogf.d(TAG, "binderDied %s", mListenerBinder);
	}

	// Because we set mIsDead to true here, we are sure mRateMap would not have new
	// elements. The propIds here is going to cover all the prop Ids that we need to
	// unregister.
	for (int i = 0; i < mRateMap.size(); i++) {
	propIds.add(mRateMap.keyAt(i));
	}
	}

	CarPropertyService.this.unregisterListenerBinderForProps(propIds, mListenerBinder);
	}

	/**
	* Calls onEvent function on the listener if the binder is alive.
	*
	* There is still chance when onEvent might fail because binderDied is not called before
	* this function.
	*/
	void onEvent(List<CarPropertyEvent> events) throws RemoteException {
	synchronized (mLock) {
	if (mIsDead) {
	return;
	}
	}
	mListener.onEvent(events);
	}
	}

	@Override
	public void init() {
	synchronized (mLock) {
	// Cache the configs list and permissions to avoid subsequent binder calls
	mConfigs = mHal.getPropertyList();
	mPropToPermission = mHal.getPermissionsForAllProperties();
	}
	if (DBG) {
	Slog.d(TAG, "cache CarPropertyConfigs " + mConfigs.size());
	}
	mHal.setListener(this);
	}

	@Override
	public void release() {
	synchronized (mLock) {
	mClientMap.clear();
	mPropIdClientMap.clear();
	mHal.setListener(null);
	mSetOperationClientMap.clear();
	}
	}

	@Override
	public void dump(IndentingPrintWriter writer) {
	writer.println("CarPropertyService");
	writer.increaseIndent();
	synchronized (mLock) {
	writer.println(String.format("There are %d clients using CarPropertyService.",
	mClientMap.size()));
	writer.println("Properties registered: ");
	writer.increaseIndent();
	for (int i = 0; i < mPropIdClientMap.size(); i++) {
	int propId = mPropIdClientMap.keyAt(i);
	writer.println("propId: 0x" + toHexString(propId)
	+ " is registered by " + mPropIdClientMap.valueAt(i).size()
	+ " client(s).");
	}
	writer.decreaseIndent();
	writer.println("Properties changed by CarPropertyService: ");
	writer.increaseIndent();
	for (int i = 0; i < mSetOperationClientMap.size(); i++) {
	int propId = mSetOperationClientMap.keyAt(i);
	SparseArray areaIdToClient = mSetOperationClientMap.valueAt(i);
	for (int j = 0; j < areaIdToClient.size(); j++) {
	int areaId = areaIdToClient.keyAt(j);
	writer.println(String.format("propId: 0x%s areaId: 0x%s by client: %s",
	toHexString(propId), toHexString(areaId), areaIdToClient.valueAt(j)));
	}
	}
	writer.decreaseIndent();
	}
	writer.decreaseIndent();
	}

	@Override
	public void registerListener(int propId, float rate, ICarPropertyEventListener listener) {
	if (DBG) {
	Slog.d(TAG, "registerListener: propId=0x" + toHexString(propId) + " rate=" + rate);
	}
	if (listener == null) {
	Slog.e(TAG, "registerListener: Listener is null.");
	throw new IllegalArgumentException("listener cannot be null.");
	}

	IBinder listenerBinder = listener.asBinder();
	CarPropertyConfig propertyConfig;
	Client finalClient;
	synchronized (mLock) {
	propertyConfig = mConfigs.get(propId);
	if (propertyConfig == null) {
	// Do not attempt to register an invalid propId
	Slog.e(TAG, "registerListener: propId is not in config list: 0x" + toHexString(
	propId));
	return;
	}
	ICarImpl.assertPermission(mContext, mHal.getReadPermission(propId));
	// Get or create the client for this listener
	Client client = mClientMap.get(listenerBinder);
	if (client == null) {
	client = new Client(listener);
	if (client.isDead()) {
	Slogf.w(TAG, "the ICarPropertyEventListener is already dead");
	return;
	}
	mClientMap.put(listenerBinder, client);
	}
	client.addProperty(propId, rate);
	// Insert the client into the propId --> clients map
	List<Client> clients = mPropIdClientMap.get(propId);
	if (clients == null) {
	clients = new ArrayList<Client>();
	mPropIdClientMap.put(propId, clients);
	}
	if (!clients.contains(client)) {
	clients.add(client);
	}
	// Set the new rate
	if (rate > mHal.getSampleRate(propId)) {
	mHal.subscribeProperty(propId, rate);
	}
	finalClient = client;
	}

	// propertyConfig and client are NonNull.
	mHandler.post(() ->
	getAndDispatchPropertyInitValue(propertyConfig, finalClient));
	}

	private void getAndDispatchPropertyInitValue(CarPropertyConfig config, Client client) {
	List<CarPropertyEvent> events = new ArrayList<>();
	int propId = config.getPropertyId();
	if (config.isGlobalProperty()) {
	CarPropertyValue value = mHal.getPropertySafe(propId, 0);
	if (value != null) {
	CarPropertyEvent event = new CarPropertyEvent(
	CarPropertyEvent.PROPERTY_EVENT_PROPERTY_CHANGE, value);
	events.add(event);
	}
	} else {
	for (int areaId : config.getAreaIds()) {
	CarPropertyValue value = mHal.getPropertySafe(propId, areaId);
	if (value != null) {
	CarPropertyEvent event = new CarPropertyEvent(
	CarPropertyEvent.PROPERTY_EVENT_PROPERTY_CHANGE, value);
	events.add(event);
	}
	}
	}
	try {
	client.onEvent(events);
	} catch (RemoteException ex) {
	// If we cannot send a record, its likely the connection snapped. Let the binder
	// death handle the situation.
	Slogf.e(TAG, "onEvent calling failed", ex);
	}
	}

	@Override
	public void unregisterListener(int propId, ICarPropertyEventListener listener) {
	if (DBG) {
	Slog.d(TAG, "unregisterListener propId=0x" + toHexString(propId));
	}
	ICarImpl.assertPermission(mContext, mHal.getReadPermission(propId));
	if (listener == null) {
	Slog.e(TAG, "unregisterListener: Listener is null.");
	throw new IllegalArgumentException("Listener is null");
	}

	IBinder listenerBinder = listener.asBinder();
	unregisterListenerBinderForProps(List.of(propId), listenerBinder);
	}

	@GuardedBy("mLock")
	private void unregisterListenerBinderLocked(int propId, IBinder listenerBinder) {
	float updateMaxRate = 0f;
	Client client = mClientMap.get(listenerBinder);
	List<Client> propertyClients = mPropIdClientMap.get(propId);
	if (mConfigs.get(propId) == null) {
	// Do not attempt to unregister an invalid propId
	Slogf.e(TAG, "unregisterListener: propId is not in config list:0x%s",
	toHexString(propId));
	return;
	}
	if ((client == null) \|\| (propertyClients == null)) {
	Slogf.e(TAG, "unregisterListenerBinderLocked: Listener was not previously "
	+ "registered.");
	} else {
	if (propertyClients.remove(client)) {
	int propLeft = client.removeProperty(propId);
	if (propLeft == 0) {
	mClientMap.remove(listenerBinder);
	}
	clearSetOperationRecorderLocked(propId, client);

	} else {
	Slogf.e(TAG, "unregisterListenerBinderLocked: Listener was not registered for "
	+ "propId=0x" + toHexString(propId));
	}

	if (propertyClients.isEmpty()) {
	// Last listener for this property unsubscribed. Clean up
	mPropIdClientMap.remove(propId);
	mSetOperationClientMap.remove(propId);
	} else {
	// Other listeners are still subscribed. Calculate the new rate
	for (int i = 0; i < propertyClients.size(); i++) {
	Client c = propertyClients.get(i);
	float rate = c.getRate(propId);
	updateMaxRate = Math.max(rate, updateMaxRate);
	}
	}
	}
	if (Float.compare(updateMaxRate, 0f) == 0) {
	// Unsubscribe property if we did not find any other client register to this property
	mHal.unsubscribeProperty(propId);
	} else if (Float.compare(updateMaxRate, mHal.getSampleRate(propId)) != 0) {
	try {
	// Only reset the sample rate if needed
	mHal.subscribeProperty(propId, updateMaxRate);
	} catch (IllegalArgumentException e) {
	Slogf.e(TAG, "failed to subscribe to propId=0x" + toHexString(propId)
	+ ", error: " + e);
	}
	}
	}

	private void unregisterListenerBinderForProps(List<Integer> propIds, IBinder listenerBinder) {
	synchronized (mLock) {
	for (int i = 0; i < propIds.size(); i++) {
	int propId = propIds.get(i);
	unregisterListenerBinderLocked(propId, listenerBinder);
	}
	}
	}

	/**
	* Return the list of properties' configs that the caller may access.
	*/
	@NonNull
	@Override
	public List<CarPropertyConfig> getPropertyList() {
	int[] allPropId;
	// Avoid permission checking under lock.
	synchronized (mLock) {
	allPropId = new int[mConfigs.size()];
	for (int i = 0; i < mConfigs.size(); i++) {
	allPropId[i] = mConfigs.keyAt(i);
	}
	}
	return getPropertyConfigList(allPropId);
	}

	/**
	*
	* @param propIds Array of property Ids
	* @return the list of properties' configs that the caller may access.
	*/
	@NonNull
	@Override
	public List<CarPropertyConfig> getPropertyConfigList(int[] propIds) {
	// Cache the granted permissions
	Set<String> grantedPermission = new HashSet<>();
	List<CarPropertyConfig> availableProp = new ArrayList<>();
	if (propIds == null) {
	return availableProp;
	}
	for (int propId : propIds) {
	String readPermission = getReadPermission(propId);
	if (readPermission == null) {
	continue;
	}
	// Check if context already granted permission first
	if (grantedPermission.contains(readPermission)
	\|\| ICarImpl.hasPermission(mContext, readPermission)) {
	grantedPermission.add(readPermission);
	synchronized (mLock) {
	availableProp.add(mConfigs.get(propId));
	}
	}
	}
	if (DBG) {
	Slog.d(TAG, "getPropertyList returns " + availableProp.size() + " configs");
	}
	return availableProp;
	}

	@Override
	public CarPropertyValue getProperty(int prop, int zone) {
	synchronized (mLock) {
	if (mConfigs.get(prop) == null) {
	// Do not attempt to register an invalid propId
	Slog.e(TAG, "getProperty: propId is not in config list:0x" + toHexString(prop));
	return null;
	}
	}
	ICarImpl.assertPermission(mContext, mHal.getReadPermission(prop));
	return mHal.getProperty(prop, zone);
	}

	/**
	* Get property value for car service's internal usage.
	* @param prop property id
	* @param zone area id
	* @return null if property is not implemented or there is an exception in the vehicle.
	*/
	public CarPropertyValue getPropertySafe(int prop, int zone) {
	synchronized (mLock) {
	if (mConfigs.get(prop) == null) {
	// Do not attempt to register an invalid propId
	Slog.e(TAG, "getPropertySafe: propId is not in config list:0x"
	+ toHexString(prop));
	return null;
	}
	}
	ICarImpl.assertPermission(mContext, mHal.getReadPermission(prop));
	return mHal.getPropertySafe(prop, zone);
	}

	@Nullable
	@Override
	public String getReadPermission(int propId) {
	Pair<String, String> permissions;
	synchronized (mLock) {
	permissions = mPropToPermission.get(propId);
	}
	if (permissions == null) {
	// Property ID does not exist
	Slog.e(TAG,
	"getReadPermission: propId is not in config list:0x" + toHexString(propId));
	return null;
	}
	return permissions.first;
	}

	@Nullable
	@Override
	public String getWritePermission(int propId) {
	Pair<String, String> permissions;
	synchronized (mLock) {
	permissions = mPropToPermission.get(propId);
	}
	if (permissions == null) {
	// Property ID does not exist
	Slog.e(TAG,
	"getWritePermission: propId is not in config list:0x" + toHexString(propId));
	return null;
	}
	return permissions.second;
	}

	@Override
	public void setProperty(CarPropertyValue prop, ICarPropertyEventListener listener) {
	int propId = prop.getPropertyId();
	checkPropertyAccessibility(propId);
	// need an extra permission for writing display units properties.
	if (mHal.isDisplayUnitsProperty(propId)) {
	ICarImpl.assertPermission(mContext, Car.PERMISSION_VENDOR_EXTENSION);
	}
	mHal.setProperty(prop);
	IBinder listenerBinder = listener.asBinder();
	synchronized (mLock) {
	Client client = mClientMap.get(listenerBinder);
	if (client == null) {
	client = new Client(listener);
	}
	if (client.isDead()) {
	Slogf.w(TAG, "the ICarPropertyEventListener is already dead");
	return;
	}
	updateSetOperationRecorderLocked(propId, prop.getAreaId(), client);
	}
	}

	// The helper method checks if the vehicle has implemented this property and the property
	// is accessible or not for platform and client.
	private void checkPropertyAccessibility(int propId) {
	// Checks if the car implemented the property or not.
	synchronized (mLock) {
	if (mConfigs.get(propId) == null) {
	throw new IllegalArgumentException("Property Id: 0x" + Integer.toHexString(propId)
	+ " does not exist in the vehicle");
	}
	}

	// Checks if android has permission to write property.
	String propertyWritePermission = mHal.getWritePermission(propId);
	if (propertyWritePermission == null) {
	throw new SecurityException("Platform does not have permission to change value for "
	+ "property Id: 0x" + Integer.toHexString(propId));
	}
	// Checks if the client has the permission.
	ICarImpl.assertPermission(mContext, propertyWritePermission);
	}

	// Updates recorder for set operation.
	@GuardedBy("mLock")
	private void updateSetOperationRecorderLocked(int propId, int areaId, Client client) {
	if (mSetOperationClientMap.get(propId) != null) {
	mSetOperationClientMap.get(propId).put(areaId, client);
	} else {
	SparseArray<Client> areaIdToClient = new SparseArray<>();
	areaIdToClient.put(areaId, client);
	mSetOperationClientMap.put(propId, areaIdToClient);
	}
	}

	// Clears map when client unregister for property.
	private void clearSetOperationRecorderLocked(int propId, Client client) {
	SparseArray<Client> areaIdToClient = mSetOperationClientMap.get(propId);
	if (areaIdToClient != null) {
	List<Integer> indexNeedToRemove = new ArrayList<>();
	for (int index = 0; index < areaIdToClient.size(); index++) {
	if (client.equals(areaIdToClient.valueAt(index))) {
	indexNeedToRemove.add(index);
	}
	}

	for (int index : indexNeedToRemove) {
	if (DBG) {
	Slog.d("ErrorEvent", " Clear propId:0x" + toHexString(propId)
	+ " areaId: 0x" + toHexString(areaIdToClient.keyAt(index)));
	}
	areaIdToClient.removeAt(index);
	}
	}
	}

	// Implement PropertyHalListener interface
	@Override
	public void onPropertyChange(List<CarPropertyEvent> events) {
	Map<Client, List<CarPropertyEvent>> eventsToDispatch = new ArrayMap<>();

	synchronized (mLock) {
	for (int i = 0; i < events.size(); i++) {
	CarPropertyEvent event = events.get(i);
	int propId = event.getCarPropertyValue().getPropertyId();
	List<Client> clients = mPropIdClientMap.get(propId);
	if (clients == null) {
	Slogf.e(TAG, "onPropertyChange: no listener registered for propId=0x%s",
	toHexString(propId));
	continue;
	}

	for (int j = 0; j < clients.size(); j++) {
	Client c = clients.get(j);
	List<CarPropertyEvent> p = eventsToDispatch.get(c);
	if (p == null) {
	// Initialize the linked list for the listener
	p = new ArrayList<CarPropertyEvent>();
	eventsToDispatch.put(c, p);
	}
	p.add(event);
	}
	}

	// Parse the dispatch list to send events
	for (Client client : eventsToDispatch.keySet()) {
	try {
	client.onEvent(eventsToDispatch.get(client));
	} catch (RemoteException ex) {
	// If we cannot send a record, its likely the connection snapped. Let binder
	// death handle the situation.
	Slogf.e(TAG, "onEvent calling failed", ex);
	}
	}
	}
	}

	@Override
	public void onPropertySetError(int property, int areaId, int errorCode) {
	Client lastOperatedClient = null;
	synchronized (mLock) {
	if (mSetOperationClientMap.get(property) != null
	&& mSetOperationClientMap.get(property).get(areaId) != null) {
	lastOperatedClient = mSetOperationClientMap.get(property).get(areaId);
	} else {
	Slog.e(TAG, "Can not find the client changed propertyId: 0x"
	+ toHexString(property) + " in areaId: 0x" + toHexString(areaId));
	}

	}
	if (lastOperatedClient != null) {
	dispatchToLastClient(property, areaId, errorCode, lastOperatedClient);
	}
	}

	private void dispatchToLastClient(int property, int areaId, int errorCode,
	Client lastOperatedClient) {
	try {
	List<CarPropertyEvent> eventList = new ArrayList<>();
	eventList.add(
	CarPropertyEvent.createErrorEventWithErrorCode(property, areaId,
	errorCode));
	lastOperatedClient.onEvent(eventList);
	} catch (RemoteException ex) {
	Slogf.e(TAG, "onEvent calling failed", ex);
	}
	}
	}