1 /*
2  * Copyright (C) 2019 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.systemui.car;
18 
19 import android.car.Car;
20 import android.content.Context;
21 
22 import androidx.annotation.AnyThread;
23 import androidx.annotation.VisibleForTesting;
24 
25 import com.android.internal.annotations.GuardedBy;
26 import com.android.systemui.car.dagger.CarSysUIDumpable;
27 
28 import java.util.ArrayList;
29 import java.util.List;
30 
31 import javax.inject.Inject;
32 import javax.inject.Singleton;
33 
34 /** Provides a common connection to the car service that can be shared. */
35 // It needs to be @Singleton scoped because it is used by a number of components in @WMSingleton &
36 // @SysUISingleton scopes.
37 @Singleton
38 public class CarServiceProvider {
39 
40     private final Context mContext;
41     /**
42      * mListeners is guarded by itself - when requiring locks on both mListeners and mCar, always
43      * obtain the car lock before the listeners.
44      */
45     @GuardedBy("mListeners")
46     private final List<CarServiceOnConnectedListener> mListeners = new ArrayList<>();
47     private final Object mCarLock = new Object();
48     /**
49      * mCar is guarded by mCarLock - when requiring locks on both mListeners and mCar, always
50      * obtain the car lock before the listeners.
51      */
52     @GuardedBy("mCarLock")
53     private Car mCar;
54     @GuardedBy("mCarLock")
55     private boolean mIsCarReady;
56 
57     @Inject
CarServiceProvider(@arSysUIDumpable Context context)58     public CarServiceProvider(@CarSysUIDumpable Context context) {
59         mContext = context;
60         mCar = Car.createCar(mContext, /* handler= */ null, Car.CAR_WAIT_TIMEOUT_DO_NOT_WAIT,
61                 (car, ready) -> {
62                     synchronized (mCarLock) {
63                         synchronized (mListeners) {
64                             mIsCarReady = ready;
65                             mCar = car;
66                             if (ready) {
67                                 for (CarServiceOnConnectedListener listener : mListeners) {
68                                     listener.onConnected(mCar);
69                                 }
70                             }
71                         }
72                     }
73                 });
74     }
75 
76     @VisibleForTesting
CarServiceProvider(Context context, Car car)77     public CarServiceProvider(Context context, Car car) {
78         mContext = context;
79         mCar = car;
80     }
81 
82     /**
83      * Let's other components hook into the connection to the car service. If we're already
84      * connected to the car service, the callback is immediately triggered.
85      */
86     @AnyThread
addListener(CarServiceOnConnectedListener listener)87     public void addListener(CarServiceOnConnectedListener listener) {
88         synchronized (mCarLock) {
89             if (mIsCarReady) {
90                 listener.onConnected(mCar);
91             }
92             synchronized (mListeners) {
93                 mListeners.add(listener);
94             }
95         }
96     }
97 
98     /**
99      * Remove a car service connection listener.
100      */
101     @AnyThread
removeListener(CarServiceOnConnectedListener listener)102     public void removeListener(CarServiceOnConnectedListener listener) {
103         synchronized (mListeners) {
104             mListeners.remove(listener);
105         }
106     }
107 
108     /**
109      * Listener which is triggered when Car Service is connected.
110      */
111     public interface CarServiceOnConnectedListener {
112         /** This will be called when the car service has successfully been connected. */
onConnected(Car car)113         void onConnected(Car car);
114     }
115 }
116