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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;
     18 
     19 import android.annotation.Nullable;
     20 import android.os.IBinder;
     21 import android.os.IInterface;
     22 import android.os.RemoteException;
     23 
     24 import java.util.Collection;
     25 import java.util.HashMap;
     26 
     27 /**
     28  * Helper class to hold client's binder interface.
     29  */
     30 public class BinderInterfaceContainer<T extends IInterface> {
     31 
     32     public static class BinderInterface<T extends IInterface>
     33             implements IBinder.DeathRecipient {
     34         public final T binderInterface;
     35         private final BinderInterfaceContainer<T> mContainer;
     36 
     37         public BinderInterface(BinderInterfaceContainer<T> container, T binderInterface) {
     38             mContainer = container;
     39             this.binderInterface = binderInterface;
     40         }
     41 
     42         @Override
     43         public void binderDied() {
     44             binderInterface.asBinder().unlinkToDeath(this, 0);
     45             mContainer.handleBinderDeath(this);
     46         }
     47     }
     48 
     49     public interface BinderEventHandler<T extends IInterface> {
     50         void onBinderDeath(BinderInterface<T> bInterface);
     51     }
     52 
     53     private final BinderEventHandler<T> mEventHandler;
     54     private final HashMap<IBinder, BinderInterface<T>> mBinders = new HashMap<>();
     55 
     56     public BinderInterfaceContainer(@Nullable BinderEventHandler<T> eventHandler) {
     57         mEventHandler = eventHandler;
     58     }
     59 
     60     public void addBinder(T binderInterface) {
     61         IBinder binder = binderInterface.asBinder();
     62         synchronized (this) {
     63             BinderInterface<T> bInterface = mBinders.get(binder);
     64             if (bInterface != null) {
     65                 return;
     66             }
     67             bInterface = new BinderInterface<T>(this, binderInterface);
     68             try {
     69                 binder.linkToDeath(bInterface, 0);
     70             } catch (RemoteException e) {
     71                 throw new IllegalArgumentException(e);
     72             }
     73             mBinders.put(binder, bInterface);
     74         }
     75     }
     76 
     77     public void removeBinder(T binderInterface) {
     78         IBinder binder = binderInterface.asBinder();
     79         synchronized(this) {
     80             BinderInterface<T> bInterface = mBinders.get(binder);
     81             if (bInterface != null) {
     82                 return;
     83             }
     84             binder.unlinkToDeath(bInterface, 0);
     85             mBinders.remove(binder);
     86         }
     87     }
     88 
     89     public BinderInterface<T> getBinderInterface(T binderInterface) {
     90         IBinder binder = binderInterface.asBinder();
     91         synchronized (this) {
     92             return mBinders.get(binder);
     93         }
     94     }
     95 
     96     public void addBinderInterface(BinderInterface<T> bInterface) {
     97         IBinder binder = bInterface.binderInterface.asBinder();
     98         synchronized (this) {
     99             try {
    100                 binder.linkToDeath(bInterface, 0);
    101             } catch (RemoteException e) {
    102                 throw new IllegalArgumentException(e);
    103             }
    104             mBinders.put(binder, bInterface);
    105         }
    106     }
    107 
    108     public Collection<BinderInterface<T>> getInterfaces() {
    109         synchronized (this) {
    110             return mBinders.values();
    111         }
    112     }
    113 
    114     public synchronized void clear() {
    115         Collection<BinderInterface<T>> interfaces = getInterfaces();
    116         for (BinderInterface<T> bInterface : interfaces) {
    117             removeBinder(bInterface.binderInterface);
    118         }
    119     }
    120 
    121     private void handleBinderDeath(BinderInterface<T> bInterface) {
    122         removeBinder(bInterface.binderInterface);
    123         if (mEventHandler != null) {
    124             mEventHandler.onBinderDeath(bInterface);
    125         }
    126     }
    127 }
    128