1 /* 2 * Copyright (C) 2018 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.server.am; 18 19 import android.content.ContentResolver; 20 import android.database.ContentObserver; 21 import android.os.Handler; 22 import android.provider.Settings; 23 import android.util.KeyValueListParser; 24 import android.util.Slog; 25 import android.util.TimeUtils; 26 27 import java.io.PrintWriter; 28 29 /** 30 * Tunable parameters for broadcast dispatch policy 31 */ 32 public class BroadcastConstants { 33 private static final String TAG = "BroadcastConstants"; 34 35 // Value element names within the Settings record 36 static final String KEY_TIMEOUT = "bcast_timeout"; 37 static final String KEY_SLOW_TIME = "bcast_slow_time"; 38 static final String KEY_DEFERRAL = "bcast_deferral"; 39 static final String KEY_DEFERRAL_DECAY_FACTOR = "bcast_deferral_decay_factor"; 40 static final String KEY_DEFERRAL_FLOOR = "bcast_deferral_floor"; 41 static final String KEY_ALLOW_BG_ACTIVITY_START_TIMEOUT = 42 "bcast_allow_bg_activity_start_timeout"; 43 44 // All time intervals are in milliseconds 45 private static final long DEFAULT_TIMEOUT = 10_000; 46 private static final long DEFAULT_SLOW_TIME = 5_000; 47 private static final long DEFAULT_DEFERRAL = 5_000; 48 private static final float DEFAULT_DEFERRAL_DECAY_FACTOR = 0.75f; 49 private static final long DEFAULT_DEFERRAL_FLOOR = 0; 50 private static final long DEFAULT_ALLOW_BG_ACTIVITY_START_TIMEOUT = 10_000; 51 52 // All time constants are in milliseconds 53 54 // Timeout period for this broadcast queue 55 public long TIMEOUT = DEFAULT_TIMEOUT; 56 // Handling time above which we declare that a broadcast recipient was "slow". Any 57 // value <= zero is interpreted as disabling broadcast deferral policy entirely. 58 public long SLOW_TIME = DEFAULT_SLOW_TIME; 59 // How long to initially defer broadcasts, if an app is slow to handle one 60 public long DEFERRAL = DEFAULT_DEFERRAL; 61 // Decay factor for successive broadcasts' deferral time 62 public float DEFERRAL_DECAY_FACTOR = DEFAULT_DEFERRAL_DECAY_FACTOR; 63 // Minimum that the deferral time can decay to until the backlog fully clears 64 public long DEFERRAL_FLOOR = DEFAULT_DEFERRAL_FLOOR; 65 // For how long after a whitelisted receiver's start its process can start a background activity 66 public long ALLOW_BG_ACTIVITY_START_TIMEOUT = DEFAULT_ALLOW_BG_ACTIVITY_START_TIMEOUT; 67 68 // Settings override tracking for this instance 69 private String mSettingsKey; 70 private SettingsObserver mSettingsObserver; 71 private ContentResolver mResolver; 72 private final KeyValueListParser mParser = new KeyValueListParser(','); 73 74 class SettingsObserver extends ContentObserver { SettingsObserver(Handler handler)75 SettingsObserver(Handler handler) { 76 super(handler); 77 } 78 79 @Override onChange(boolean selfChange)80 public void onChange(boolean selfChange) { 81 updateConstants(); 82 } 83 } 84 85 // A given constants instance is configured to observe specific keys from which 86 // that instance's values are drawn. BroadcastConstants(String settingsKey)87 public BroadcastConstants(String settingsKey) { 88 mSettingsKey = settingsKey; 89 } 90 91 /** 92 * Spin up the observer lazily, since it can only happen once the settings provider 93 * has been brought into service 94 */ startObserving(Handler handler, ContentResolver resolver)95 public void startObserving(Handler handler, ContentResolver resolver) { 96 mResolver = resolver; 97 98 mSettingsObserver = new SettingsObserver(handler); 99 mResolver.registerContentObserver(Settings.Global.getUriFor(mSettingsKey), 100 false, mSettingsObserver); 101 102 updateConstants(); 103 } 104 updateConstants()105 private void updateConstants() { 106 synchronized (mParser) { 107 try { 108 mParser.setString(Settings.Global.getString(mResolver, mSettingsKey)); 109 } catch (IllegalArgumentException e) { 110 Slog.e(TAG, "Bad broadcast settings in key '" + mSettingsKey + "'", e); 111 return; 112 } 113 114 // Unspecified fields retain their current value rather than revert to default 115 TIMEOUT = mParser.getLong(KEY_TIMEOUT, TIMEOUT); 116 SLOW_TIME = mParser.getLong(KEY_SLOW_TIME, SLOW_TIME); 117 DEFERRAL = mParser.getLong(KEY_DEFERRAL, DEFERRAL); 118 DEFERRAL_DECAY_FACTOR = mParser.getFloat(KEY_DEFERRAL_DECAY_FACTOR, 119 DEFERRAL_DECAY_FACTOR); 120 DEFERRAL_FLOOR = mParser.getLong(KEY_DEFERRAL_FLOOR, DEFERRAL_FLOOR); 121 ALLOW_BG_ACTIVITY_START_TIMEOUT = mParser.getLong(KEY_ALLOW_BG_ACTIVITY_START_TIMEOUT, 122 ALLOW_BG_ACTIVITY_START_TIMEOUT); 123 } 124 } 125 126 /** 127 * Standard dumpsys support; invoked from BroadcastQueue dump 128 */ dump(PrintWriter pw)129 public void dump(PrintWriter pw) { 130 synchronized (mParser) { 131 pw.println(); 132 pw.print(" Broadcast parameters (key="); 133 pw.print(mSettingsKey); 134 pw.print(", observing="); 135 pw.print(mSettingsObserver != null); 136 pw.println("):"); 137 138 pw.print(" "); pw.print(KEY_TIMEOUT); pw.print(" = "); 139 TimeUtils.formatDuration(TIMEOUT, pw); 140 pw.println(); 141 142 pw.print(" "); pw.print(KEY_SLOW_TIME); pw.print(" = "); 143 TimeUtils.formatDuration(SLOW_TIME, pw); 144 pw.println(); 145 146 pw.print(" "); pw.print(KEY_DEFERRAL); pw.print(" = "); 147 TimeUtils.formatDuration(DEFERRAL, pw); 148 pw.println(); 149 150 pw.print(" "); pw.print(KEY_DEFERRAL_DECAY_FACTOR); pw.print(" = "); 151 pw.println(DEFERRAL_DECAY_FACTOR); 152 153 pw.print(" "); pw.print(KEY_DEFERRAL_FLOOR); pw.print(" = "); 154 TimeUtils.formatDuration(DEFERRAL_FLOOR, pw); 155 156 pw.print(" "); pw.print(KEY_ALLOW_BG_ACTIVITY_START_TIMEOUT); pw.print(" = "); 157 TimeUtils.formatDuration(ALLOW_BG_ACTIVITY_START_TIMEOUT, pw); 158 pw.println(); 159 } 160 } 161 } 162