1 /* 2 * Copyright (C) 2022 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.util.service; 18 19 import android.content.BroadcastReceiver; 20 import android.content.ComponentName; 21 import android.content.Context; 22 import android.content.Intent; 23 import android.content.IntentFilter; 24 import android.os.PatternMatcher; 25 import android.util.Log; 26 27 import com.google.android.collect.Lists; 28 29 import java.lang.ref.WeakReference; 30 import java.util.ArrayList; 31 import java.util.Iterator; 32 33 import javax.inject.Inject; 34 35 /** 36 * {@link PackageObserver} allows for monitoring the system for changes relating to a particular 37 * package. This can be used by clients to detect when a related package has changed and reloading 38 * is necessary. 39 */ 40 public class PackageObserver implements Observer { 41 private static final String TAG = "PackageObserver"; 42 private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG); 43 44 private final ArrayList<WeakReference<Callback>> mCallbacks = Lists.newArrayList(); 45 46 private final BroadcastReceiver mReceiver = new BroadcastReceiver() { 47 @Override 48 public void onReceive(Context context, Intent intent) { 49 if (DEBUG) { 50 Log.d(TAG, "package added receiver - onReceive"); 51 } 52 53 final Iterator<WeakReference<Callback>> iter = mCallbacks.iterator(); 54 while (iter.hasNext()) { 55 final Callback callback = iter.next().get(); 56 if (callback != null) { 57 callback.onSourceChanged(); 58 } else { 59 iter.remove(); 60 } 61 } 62 } 63 }; 64 65 private final String mPackageName; 66 private final Context mContext; 67 68 @Inject PackageObserver(Context context, ComponentName component)69 public PackageObserver(Context context, ComponentName component) { 70 mContext = context; 71 mPackageName = component.getPackageName(); 72 } 73 74 @Override addCallback(Callback callback)75 public void addCallback(Callback callback) { 76 if (DEBUG) { 77 Log.d(TAG, "addCallback:" + callback); 78 } 79 mCallbacks.add(new WeakReference<>(callback)); 80 81 // Only register for listening to package additions on first callback. 82 if (mCallbacks.size() > 1) { 83 return; 84 } 85 86 final IntentFilter filter = new IntentFilter(Intent.ACTION_PACKAGE_ADDED); 87 filter.addDataScheme("package"); 88 filter.addDataSchemeSpecificPart(mPackageName, PatternMatcher.PATTERN_LITERAL); 89 // Note that we directly register the receiver here as data schemes are not supported by 90 // BroadcastDispatcher. 91 mContext.registerReceiver(mReceiver, filter, Context.RECEIVER_EXPORTED); 92 } 93 94 @Override removeCallback(Callback callback)95 public void removeCallback(Callback callback) { 96 if (DEBUG) { 97 Log.d(TAG, "removeCallback:" + callback); 98 } 99 final boolean removed = mCallbacks.removeIf(el -> el.get() == callback); 100 101 if (removed && mCallbacks.isEmpty()) { 102 mContext.unregisterReceiver(mReceiver); 103 } 104 } 105 } 106