/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.server.am;
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import android.content.ContentResolver;
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import android.database.ContentObserver;
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import android.os.Handler;
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import android.provider.Settings;
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import android.util.KeyValueListParser;
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import android.util.Slog;
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import android.util.TimeUtils;
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import java.io.PrintWriter;
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/**
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* Tunable parameters for broadcast dispatch policy
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*/
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public class BroadcastConstants {
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private static final String TAG = "BroadcastConstants";
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// Value element names within the Settings record
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static final String KEY_TIMEOUT = "bcast_timeout";
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static final String KEY_SLOW_TIME = "bcast_slow_time";
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static final String KEY_DEFERRAL = "bcast_deferral";
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static final String KEY_DEFERRAL_DECAY_FACTOR = "bcast_deferral_decay_factor";
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static final String KEY_DEFERRAL_FLOOR = "bcast_deferral_floor";
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static final String KEY_ALLOW_BG_ACTIVITY_START_TIMEOUT =
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"bcast_allow_bg_activity_start_timeout";
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// All time intervals are in milliseconds
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private static final long DEFAULT_TIMEOUT = 10_000;
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private static final long DEFAULT_SLOW_TIME = 5_000;
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private static final long DEFAULT_DEFERRAL = 5_000;
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private static final float DEFAULT_DEFERRAL_DECAY_FACTOR = 0.75f;
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private static final long DEFAULT_DEFERRAL_FLOOR = 0;
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private static final long DEFAULT_ALLOW_BG_ACTIVITY_START_TIMEOUT = 10_000;
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// All time constants are in milliseconds
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// Timeout period for this broadcast queue
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public long TIMEOUT = DEFAULT_TIMEOUT;
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// Handling time above which we declare that a broadcast recipient was "slow". Any
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// value <= zero is interpreted as disabling broadcast deferral policy entirely.
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public long SLOW_TIME = DEFAULT_SLOW_TIME;
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// How long to initially defer broadcasts, if an app is slow to handle one
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public long DEFERRAL = DEFAULT_DEFERRAL;
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// Decay factor for successive broadcasts' deferral time
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public float DEFERRAL_DECAY_FACTOR = DEFAULT_DEFERRAL_DECAY_FACTOR;
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// Minimum that the deferral time can decay to until the backlog fully clears
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public long DEFERRAL_FLOOR = DEFAULT_DEFERRAL_FLOOR;
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// For how long after a whitelisted receiver's start its process can start a background activity
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public long ALLOW_BG_ACTIVITY_START_TIMEOUT = DEFAULT_ALLOW_BG_ACTIVITY_START_TIMEOUT;
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// Settings override tracking for this instance
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private String mSettingsKey;
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private SettingsObserver mSettingsObserver;
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private ContentResolver mResolver;
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private final KeyValueListParser mParser = new KeyValueListParser(',');
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class SettingsObserver extends ContentObserver {
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SettingsObserver(Handler handler) {
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super(handler);
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}
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@Override
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public void onChange(boolean selfChange) {
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updateConstants();
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}
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}
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// A given constants instance is configured to observe specific keys from which
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// that instance's values are drawn.
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public BroadcastConstants(String settingsKey) {
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mSettingsKey = settingsKey;
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}
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/**
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* Spin up the observer lazily, since it can only happen once the settings provider
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* has been brought into service
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*/
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public void startObserving(Handler handler, ContentResolver resolver) {
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mResolver = resolver;
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mSettingsObserver = new SettingsObserver(handler);
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mResolver.registerContentObserver(Settings.Global.getUriFor(mSettingsKey),
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false, mSettingsObserver);
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updateConstants();
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}
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private void updateConstants() {
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synchronized (mParser) {
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try {
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mParser.setString(Settings.Global.getString(mResolver, mSettingsKey));
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} catch (IllegalArgumentException e) {
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Slog.e(TAG, "Bad broadcast settings in key '" + mSettingsKey + "'", e);
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return;
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}
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// Unspecified fields retain their current value rather than revert to default
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TIMEOUT = mParser.getLong(KEY_TIMEOUT, TIMEOUT);
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SLOW_TIME = mParser.getLong(KEY_SLOW_TIME, SLOW_TIME);
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DEFERRAL = mParser.getLong(KEY_DEFERRAL, DEFERRAL);
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DEFERRAL_DECAY_FACTOR = mParser.getFloat(KEY_DEFERRAL_DECAY_FACTOR,
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DEFERRAL_DECAY_FACTOR);
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DEFERRAL_FLOOR = mParser.getLong(KEY_DEFERRAL_FLOOR, DEFERRAL_FLOOR);
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ALLOW_BG_ACTIVITY_START_TIMEOUT = mParser.getLong(KEY_ALLOW_BG_ACTIVITY_START_TIMEOUT,
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ALLOW_BG_ACTIVITY_START_TIMEOUT);
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}
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}
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/**
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* Standard dumpsys support; invoked from BroadcastQueue dump
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*/
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public void dump(PrintWriter pw) {
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synchronized (mParser) {
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pw.println();
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pw.print(" Broadcast parameters (key=");
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pw.print(mSettingsKey);
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pw.print(", observing=");
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pw.print(mSettingsObserver != null);
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pw.println("):");
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pw.print(" "); pw.print(KEY_TIMEOUT); pw.print(" = ");
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TimeUtils.formatDuration(TIMEOUT, pw);
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pw.println();
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pw.print(" "); pw.print(KEY_SLOW_TIME); pw.print(" = ");
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TimeUtils.formatDuration(SLOW_TIME, pw);
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pw.println();
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pw.print(" "); pw.print(KEY_DEFERRAL); pw.print(" = ");
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TimeUtils.formatDuration(DEFERRAL, pw);
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pw.println();
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pw.print(" "); pw.print(KEY_DEFERRAL_DECAY_FACTOR); pw.print(" = ");
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pw.println(DEFERRAL_DECAY_FACTOR);
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pw.print(" "); pw.print(KEY_DEFERRAL_FLOOR); pw.print(" = ");
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TimeUtils.formatDuration(DEFERRAL_FLOOR, pw);
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pw.print(" "); pw.print(KEY_ALLOW_BG_ACTIVITY_START_TIMEOUT); pw.print(" = ");
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TimeUtils.formatDuration(ALLOW_BG_ACTIVITY_START_TIMEOUT, pw);
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pw.println();
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}
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}
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}
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