services/core/java/com/android/server/BatteryService.java

/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.server;

import android.app.ActivityManagerInternal;
import android.database.ContentObserver;
import android.os.BatteryStats;

import android.os.PowerManager;
import android.os.ResultReceiver;
import android.os.ShellCallback;
import android.os.ShellCommand;
import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.app.IBatteryStats;
import com.android.internal.util.DumpUtils;
import com.android.server.am.BatteryStatsService;
import com.android.server.lights.Light;
import com.android.server.lights.LightsManager;

import android.app.ActivityManager;
import android.content.ContentResolver;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.hidl.manager.V1_0.IServiceManager;
import android.hidl.manager.V1_0.IServiceNotification;
import android.hardware.health.V2_0.HealthInfo;
import android.hardware.health.V2_0.IHealthInfoCallback;
import android.hardware.health.V2_0.IHealth;
import android.hardware.health.V2_0.Result;
import android.os.BatteryManager;
import android.os.BatteryManagerProto;
import android.os.BatteryManagerInternal;
import android.os.BatteryProperty;
import android.os.Binder;
import android.os.FileUtils;
import android.os.Handler;
import android.os.IBatteryPropertiesListener;
import android.os.IBatteryPropertiesRegistrar;
import android.os.IBinder;
import android.os.DropBoxManager;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.os.SystemClock;
import android.os.UEventObserver;
import android.os.UserHandle;
import android.provider.Settings;
import android.service.battery.BatteryServiceDumpProto;
import android.util.EventLog;
import android.util.MutableInt;
import android.util.Slog;
import android.util.proto.ProtoOutputStream;

import java.io.File;
import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintWriter;

import java.util.Arrays;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.concurrent.atomic.AtomicReference;

/**
 * <p>BatteryService monitors the charging status, and charge level of the device
 * battery.  When these values change this service broadcasts the new values
 * to all {@link android.content.BroadcastReceiver IntentReceivers} that are
 * watching the {@link android.content.Intent#ACTION_BATTERY_CHANGED
 * BATTERY_CHANGED} action.</p>
 * <p>The new values are stored in the Intent data and can be retrieved by
 * calling {@link android.content.Intent#getExtra Intent.getExtra} with the
 * following keys:</p>
 * <p>&quot;scale&quot; - int, the maximum value for the charge level</p>
 * <p>&quot;level&quot; - int, charge level, from 0 through &quot;scale&quot; inclusive</p>
 * <p>&quot;status&quot; - String, the current charging status.<br />
 * <p>&quot;health&quot; - String, the current battery health.<br />
 * <p>&quot;present&quot; - boolean, true if the battery is present<br />
 * <p>&quot;icon-small&quot; - int, suggested small icon to use for this state</p>
 * <p>&quot;plugged&quot; - int, 0 if the device is not plugged in; 1 if plugged
 * into an AC power adapter; 2 if plugged in via USB.</p>
 * <p>&quot;voltage&quot; - int, current battery voltage in millivolts</p>
 * <p>&quot;temperature&quot; - int, current battery temperature in tenths of
 * a degree Centigrade</p>
 * <p>&quot;technology&quot; - String, the type of battery installed, e.g. "Li-ion"</p>
 *
 * <p>
 * The battery service may be called by the power manager while holding its locks so
 * we take care to post all outcalls into the activity manager to a handler.
 *
 * FIXME: Ideally the power manager would perform all of its calls into the battery
 * service asynchronously itself.
 * </p>
 */
public final class BatteryService extends SystemService {
    private static final String TAG = BatteryService.class.getSimpleName();

    private static final boolean DEBUG = false;

    private static final int BATTERY_SCALE = 100;    // battery capacity is a percentage

    private static final long HEALTH_HAL_WAIT_MS = 1000;

    // Used locally for determining when to make a last ditch effort to log
    // discharge stats before the device dies.
    private int mCriticalBatteryLevel;

    private static final String[] DUMPSYS_ARGS = new String[] { "--checkin", "--unplugged" };

    private static final String DUMPSYS_DATA_PATH = "/data/system/";

    // This should probably be exposed in the API, though it's not critical
    private static final int BATTERY_PLUGGED_NONE = 0;

    private final Context mContext;
    private final IBatteryStats mBatteryStats;
    BinderService mBinderService;
    private final Handler mHandler;

    private final Object mLock = new Object();

    private HealthInfo mHealthInfo;
    private final HealthInfo mLastHealthInfo = new HealthInfo();
    private boolean mBatteryLevelCritical;
    private int mLastBatteryStatus;
    private int mLastBatteryHealth;
    private boolean mLastBatteryPresent;
    private int mLastBatteryLevel;
    private int mLastBatteryVoltage;
    private int mLastBatteryTemperature;
    private boolean mLastBatteryLevelCritical;
    private int mLastMaxChargingCurrent;
    private int mLastMaxChargingVoltage;
    private int mLastChargeCounter;

    private int mSequence = 1;

    private int mInvalidCharger;
    private int mLastInvalidCharger;

    private int mLowBatteryWarningLevel;
    private int mLowBatteryCloseWarningLevel;
    private int mShutdownBatteryTemperature;

    private int mPlugType;
    private int mLastPlugType = -1; // Extra state so we can detect first run

    private boolean mBatteryLevelLow;

    private long mDischargeStartTime;
    private int mDischargeStartLevel;

    private boolean mUpdatesStopped;

    private Led mLed;

    private boolean mSentLowBatteryBroadcast = false;

    private ActivityManagerInternal mActivityManagerInternal;

    private HealthServiceWrapper mHealthServiceWrapper;
    private HealthHalCallback mHealthHalCallback;
    private BatteryPropertiesRegistrar mBatteryPropertiesRegistrar;

    public BatteryService(Context context) {
        super(context);

        mContext = context;
        mHandler = new Handler(true /*async*/);
        mLed = new Led(context, getLocalService(LightsManager.class));
        mBatteryStats = BatteryStatsService.getService();
        mActivityManagerInternal = LocalServices.getService(ActivityManagerInternal.class);

        mCriticalBatteryLevel = mContext.getResources().getInteger(
                com.android.internal.R.integer.config_criticalBatteryWarningLevel);
        mLowBatteryWarningLevel = mContext.getResources().getInteger(
                com.android.internal.R.integer.config_lowBatteryWarningLevel);
        mLowBatteryCloseWarningLevel = mLowBatteryWarningLevel + mContext.getResources().getInteger(
                com.android.internal.R.integer.config_lowBatteryCloseWarningBump);
        mShutdownBatteryTemperature = mContext.getResources().getInteger(
                com.android.internal.R.integer.config_shutdownBatteryTemperature);

        // watch for invalid charger messages if the invalid_charger switch exists
        if (new File("/sys/devices/virtual/switch/invalid_charger/state").exists()) {
            UEventObserver invalidChargerObserver = new UEventObserver() {
                @Override
                public void onUEvent(UEvent event) {
                    final int invalidCharger = "1".equals(event.get("SWITCH_STATE")) ? 1 : 0;
                    synchronized (mLock) {
                        if (mInvalidCharger != invalidCharger) {
                            mInvalidCharger = invalidCharger;
                        }
                    }
                }
            };
            invalidChargerObserver.startObserving(
                    "DEVPATH=/devices/virtual/switch/invalid_charger");
        }
    }

    @Override
    public void onStart() {
        registerHealthCallback();

        mBinderService = new BinderService();
        publishBinderService("battery", mBinderService);
        mBatteryPropertiesRegistrar = new BatteryPropertiesRegistrar();
        publishBinderService("batteryproperties", mBatteryPropertiesRegistrar);
        publishLocalService(BatteryManagerInternal.class, new LocalService());
    }

    @Override
    public void onBootPhase(int phase) {
        if (phase == PHASE_ACTIVITY_MANAGER_READY) {
            // check our power situation now that it is safe to display the shutdown dialog.
            synchronized (mLock) {
                ContentObserver obs = new ContentObserver(mHandler) {
                    @Override
                    public void onChange(boolean selfChange) {
                        synchronized (mLock) {
                            updateBatteryWarningLevelLocked();
                        }
                    }
                };
                final ContentResolver resolver = mContext.getContentResolver();
                resolver.registerContentObserver(Settings.Global.getUriFor(
                        Settings.Global.LOW_POWER_MODE_TRIGGER_LEVEL),
                        false, obs, UserHandle.USER_ALL);
                updateBatteryWarningLevelLocked();
            }
        }
    }

    private void registerHealthCallback() {
        mHealthServiceWrapper = new HealthServiceWrapper();
        mHealthHalCallback = new HealthHalCallback();
        // IHealth is lazily retrieved.
        try {
            mHealthServiceWrapper.init(mHealthHalCallback,
                    new HealthServiceWrapper.IServiceManagerSupplier() {},
                    new HealthServiceWrapper.IHealthSupplier() {});
        } catch (RemoteException ex) {
            Slog.e(TAG, "health: cannot register callback. (RemoteException)");
            throw ex.rethrowFromSystemServer();
        } catch (NoSuchElementException ex) {
            Slog.e(TAG, "health: cannot register callback. (no supported health HAL service)");
            throw ex;
        }

        // init register for new service notifications, and IServiceManager should return the
        // existing service in a near future. Wait for this.update() to instantiate
        // the initial mHealthInfo.
        long beforeWait = SystemClock.uptimeMillis();
        synchronized (mLock) {
            while (mHealthInfo == null) {
                Slog.i(TAG, "health: Waited " + (SystemClock.uptimeMillis() - beforeWait) +
                        "ms for callbacks. Waiting another " + HEALTH_HAL_WAIT_MS + " ms...");
                try {
                    mLock.wait(HEALTH_HAL_WAIT_MS);
                } catch (InterruptedException ex) {
                    Slog.i(TAG, "health: InterruptedException when waiting for update. "
                        + " Continuing...");
                }
            }
        }

        Slog.i(TAG, "health: Waited " + (SystemClock.uptimeMillis() - beforeWait)
                + "ms and received the update.");
    }

    private void updateBatteryWarningLevelLocked() {
        final ContentResolver resolver = mContext.getContentResolver();
        int defWarnLevel = mContext.getResources().getInteger(
                com.android.internal.R.integer.config_lowBatteryWarningLevel);
        mLowBatteryWarningLevel = Settings.Global.getInt(resolver,
                Settings.Global.LOW_POWER_MODE_TRIGGER_LEVEL, defWarnLevel);
        if (mLowBatteryWarningLevel == 0) {
            mLowBatteryWarningLevel = defWarnLevel;
        }
        if (mLowBatteryWarningLevel < mCriticalBatteryLevel) {
            mLowBatteryWarningLevel = mCriticalBatteryLevel;
        }
        mLowBatteryCloseWarningLevel = mLowBatteryWarningLevel + mContext.getResources().getInteger(
                com.android.internal.R.integer.config_lowBatteryCloseWarningBump);
        processValuesLocked(true);
    }

    private boolean isPoweredLocked(int plugTypeSet) {
        // assume we are powered if battery state is unknown so
        // the "stay on while plugged in" option will work.
        if (mHealthInfo.legacy.batteryStatus == BatteryManager.BATTERY_STATUS_UNKNOWN) {
            return true;
        }
        if ((plugTypeSet & BatteryManager.BATTERY_PLUGGED_AC) != 0 && mHealthInfo.legacy.chargerAcOnline) {
            return true;
        }
        if ((plugTypeSet & BatteryManager.BATTERY_PLUGGED_USB) != 0 && mHealthInfo.legacy.chargerUsbOnline) {
            return true;
        }
        if ((plugTypeSet & BatteryManager.BATTERY_PLUGGED_WIRELESS) != 0 && mHealthInfo.legacy.chargerWirelessOnline) {
            return true;
        }
        return false;
    }

    private boolean shouldSendBatteryLowLocked() {
        final boolean plugged = mPlugType != BATTERY_PLUGGED_NONE;
        final boolean oldPlugged = mLastPlugType != BATTERY_PLUGGED_NONE;

        /* The ACTION_BATTERY_LOW broadcast is sent in these situations:
         * - is just un-plugged (previously was plugged) and battery level is
         *   less than or equal to WARNING, or
         * - is not plugged and battery level falls to WARNING boundary
         *   (becomes <= mLowBatteryWarningLevel).
         */
        return !plugged
                && mHealthInfo.legacy.batteryStatus != BatteryManager.BATTERY_STATUS_UNKNOWN
                && mHealthInfo.legacy.batteryLevel <= mLowBatteryWarningLevel
                && (oldPlugged || mLastBatteryLevel > mLowBatteryWarningLevel);
    }

    private void shutdownIfNoPowerLocked() {
        // shut down gracefully if our battery is critically low and we are not powered.
        // wait until the system has booted before attempting to display the shutdown dialog.
        if (mHealthInfo.legacy.batteryLevel == 0 && !isPoweredLocked(BatteryManager.BATTERY_PLUGGED_ANY)) {
            mHandler.post(new Runnable() {
                @Override
                public void run() {
                    if (mActivityManagerInternal.isSystemReady()) {
                        Intent intent = new Intent(Intent.ACTION_REQUEST_SHUTDOWN);
                        intent.putExtra(Intent.EXTRA_KEY_CONFIRM, false);
                        intent.putExtra(Intent.EXTRA_REASON,
                                PowerManager.SHUTDOWN_LOW_BATTERY);
                        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                        mContext.startActivityAsUser(intent, UserHandle.CURRENT);
                    }
                }
            });
        }
    }

    private void shutdownIfOverTempLocked() {
        // shut down gracefully if temperature is too high (> 68.0C by default)
        // wait until the system has booted before attempting to display the
        // shutdown dialog.
        if (mHealthInfo.legacy.batteryTemperature > mShutdownBatteryTemperature) {
            mHandler.post(new Runnable() {
                @Override
                public void run() {
                    if (mActivityManagerInternal.isSystemReady()) {
                        Intent intent = new Intent(Intent.ACTION_REQUEST_SHUTDOWN);
                        intent.putExtra(Intent.EXTRA_KEY_CONFIRM, false);
                        intent.putExtra(Intent.EXTRA_REASON,
                                PowerManager.SHUTDOWN_BATTERY_THERMAL_STATE);
                        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                        mContext.startActivityAsUser(intent, UserHandle.CURRENT);
                    }
                }
            });
        }
    }

    private void update(HealthInfo info) {
        synchronized (mLock) {
            if (!mUpdatesStopped) {
                mHealthInfo = info;
                // Process the new values.
                processValuesLocked(false);
                mLock.notifyAll(); // for any waiters on new info
            } else {
                copy(mLastHealthInfo, info);
            }
        }
    }

    private static void copy(HealthInfo dst, HealthInfo src) {
        dst.legacy.chargerAcOnline = src.legacy.chargerAcOnline;
        dst.legacy.chargerUsbOnline = src.legacy.chargerUsbOnline;
        dst.legacy.chargerWirelessOnline = src.legacy.chargerWirelessOnline;
        dst.legacy.maxChargingCurrent = src.legacy.maxChargingCurrent;
        dst.legacy.maxChargingVoltage = src.legacy.maxChargingVoltage;
        dst.legacy.batteryStatus = src.legacy.batteryStatus;
        dst.legacy.batteryHealth = src.legacy.batteryHealth;
        dst.legacy.batteryPresent = src.legacy.batteryPresent;
        dst.legacy.batteryLevel = src.legacy.batteryLevel;
        dst.legacy.batteryVoltage = src.legacy.batteryVoltage;
        dst.legacy.batteryTemperature = src.legacy.batteryTemperature;
        dst.legacy.batteryCurrent = src.legacy.batteryCurrent;
        dst.legacy.batteryCycleCount = src.legacy.batteryCycleCount;
        dst.legacy.batteryFullCharge = src.legacy.batteryFullCharge;
        dst.legacy.batteryChargeCounter = src.legacy.batteryChargeCounter;
        dst.legacy.batteryTechnology = src.legacy.batteryTechnology;
        dst.batteryCurrentAverage = src.batteryCurrentAverage;
        dst.batteryCapacity = src.batteryCapacity;
        dst.energyCounter = src.energyCounter;
    }

    private void processValuesLocked(boolean force) {
        boolean logOutlier = false;
        long dischargeDuration = 0;

        mBatteryLevelCritical = (mHealthInfo.legacy.batteryLevel <= mCriticalBatteryLevel);
        if (mHealthInfo.legacy.chargerAcOnline) {
            mPlugType = BatteryManager.BATTERY_PLUGGED_AC;
        } else if (mHealthInfo.legacy.chargerUsbOnline) {
            mPlugType = BatteryManager.BATTERY_PLUGGED_USB;
        } else if (mHealthInfo.legacy.chargerWirelessOnline) {
            mPlugType = BatteryManager.BATTERY_PLUGGED_WIRELESS;
        } else {
            mPlugType = BATTERY_PLUGGED_NONE;
        }

        if (DEBUG) {
            Slog.d(TAG, "Processing new values: "
                    + "info=" + mHealthInfo
                    + ", mBatteryLevelCritical=" + mBatteryLevelCritical
                    + ", mPlugType=" + mPlugType);
        }

        // Let the battery stats keep track of the current level.
        try {
            mBatteryStats.setBatteryState(mHealthInfo.legacy.batteryStatus, mHealthInfo.legacy.batteryHealth,
                    mPlugType, mHealthInfo.legacy.batteryLevel, mHealthInfo.legacy.batteryTemperature,
                    mHealthInfo.legacy.batteryVoltage, mHealthInfo.legacy.batteryChargeCounter,
                    mHealthInfo.legacy.batteryFullCharge);
        } catch (RemoteException e) {
            // Should never happen.
        }

        shutdownIfNoPowerLocked();
        shutdownIfOverTempLocked();

        if (force || (mHealthInfo.legacy.batteryStatus != mLastBatteryStatus ||
                mHealthInfo.legacy.batteryHealth != mLastBatteryHealth ||
                mHealthInfo.legacy.batteryPresent != mLastBatteryPresent ||
                mHealthInfo.legacy.batteryLevel != mLastBatteryLevel ||
                mPlugType != mLastPlugType ||
                mHealthInfo.legacy.batteryVoltage != mLastBatteryVoltage ||
                mHealthInfo.legacy.batteryTemperature != mLastBatteryTemperature ||
                mHealthInfo.legacy.maxChargingCurrent != mLastMaxChargingCurrent ||
                mHealthInfo.legacy.maxChargingVoltage != mLastMaxChargingVoltage ||
                mHealthInfo.legacy.batteryChargeCounter != mLastChargeCounter ||
                mInvalidCharger != mLastInvalidCharger)) {

            if (mPlugType != mLastPlugType) {
                if (mLastPlugType == BATTERY_PLUGGED_NONE) {
                    // discharging -> charging

                    // There's no value in this data unless we've discharged at least once and the
                    // battery level has changed; so don't log until it does.
                    if (mDischargeStartTime != 0 && mDischargeStartLevel != mHealthInfo.legacy.batteryLevel) {
                        dischargeDuration = SystemClock.elapsedRealtime() - mDischargeStartTime;
                        logOutlier = true;
                        EventLog.writeEvent(EventLogTags.BATTERY_DISCHARGE, dischargeDuration,
                                mDischargeStartLevel, mHealthInfo.legacy.batteryLevel);
                        // make sure we see a discharge event before logging again
                        mDischargeStartTime = 0;
                    }
                } else if (mPlugType == BATTERY_PLUGGED_NONE) {
                    // charging -> discharging or we just powered up
                    mDischargeStartTime = SystemClock.elapsedRealtime();
                    mDischargeStartLevel = mHealthInfo.legacy.batteryLevel;
                }
            }
            if (mHealthInfo.legacy.batteryStatus != mLastBatteryStatus ||
                    mHealthInfo.legacy.batteryHealth != mLastBatteryHealth ||
                    mHealthInfo.legacy.batteryPresent != mLastBatteryPresent ||
                    mPlugType != mLastPlugType) {
                EventLog.writeEvent(EventLogTags.BATTERY_STATUS,
                        mHealthInfo.legacy.batteryStatus, mHealthInfo.legacy.batteryHealth, mHealthInfo.legacy.batteryPresent ? 1 : 0,
                        mPlugType, mHealthInfo.legacy.batteryTechnology);
            }
            if (mHealthInfo.legacy.batteryLevel != mLastBatteryLevel) {
                // Don't do this just from voltage or temperature changes, that is
                // too noisy.
                EventLog.writeEvent(EventLogTags.BATTERY_LEVEL,
                        mHealthInfo.legacy.batteryLevel, mHealthInfo.legacy.batteryVoltage, mHealthInfo.legacy.batteryTemperature);
            }
            if (mBatteryLevelCritical && !mLastBatteryLevelCritical &&
                    mPlugType == BATTERY_PLUGGED_NONE) {
                // We want to make sure we log discharge cycle outliers
                // if the battery is about to die.
                dischargeDuration = SystemClock.elapsedRealtime() - mDischargeStartTime;
                logOutlier = true;
            }

            if (!mBatteryLevelLow) {
                // Should we now switch in to low battery mode?
                if (mPlugType == BATTERY_PLUGGED_NONE
                        && mHealthInfo.legacy.batteryLevel <= mLowBatteryWarningLevel) {
                    mBatteryLevelLow = true;
                }
            } else {
                // Should we now switch out of low battery mode?
                if (mPlugType != BATTERY_PLUGGED_NONE) {
                    mBatteryLevelLow = false;
                } else if (mHealthInfo.legacy.batteryLevel >= mLowBatteryCloseWarningLevel)  {
                    mBatteryLevelLow = false;
                } else if (force && mHealthInfo.legacy.batteryLevel >= mLowBatteryWarningLevel) {
                    // If being forced, the previous state doesn't matter, we will just
                    // absolutely check to see if we are now above the warning level.
                    mBatteryLevelLow = false;
                }
            }

            mSequence++;

            // Separate broadcast is sent for power connected / not connected
            // since the standard intent will not wake any applications and some
            // applications may want to have smart behavior based on this.
            if (mPlugType != 0 && mLastPlugType == 0) {
                final Intent statusIntent = new Intent(Intent.ACTION_POWER_CONNECTED);
                statusIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
                statusIntent.putExtra(BatteryManager.EXTRA_SEQUENCE, mSequence);
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
                    }
                });
            }
            else if (mPlugType == 0 && mLastPlugType != 0) {
                final Intent statusIntent = new Intent(Intent.ACTION_POWER_DISCONNECTED);
                statusIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
                statusIntent.putExtra(BatteryManager.EXTRA_SEQUENCE, mSequence);
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
                    }
                });
            }

            if (shouldSendBatteryLowLocked()) {
                mSentLowBatteryBroadcast = true;
                final Intent statusIntent = new Intent(Intent.ACTION_BATTERY_LOW);
                statusIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
                statusIntent.putExtra(BatteryManager.EXTRA_SEQUENCE, mSequence);
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
                    }
                });
            } else if (mSentLowBatteryBroadcast &&
                    mHealthInfo.legacy.batteryLevel >= mLowBatteryCloseWarningLevel) {
                mSentLowBatteryBroadcast = false;
                final Intent statusIntent = new Intent(Intent.ACTION_BATTERY_OKAY);
                statusIntent.setFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
                statusIntent.putExtra(BatteryManager.EXTRA_SEQUENCE, mSequence);
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        mContext.sendBroadcastAsUser(statusIntent, UserHandle.ALL);
                    }
                });
            }

            // We are doing this after sending the above broadcasts, so anything processing
            // them will get the new sequence number at that point.  (See for example how testing
            // of JobScheduler's BatteryController works.)
            sendIntentLocked();

            // Update the battery LED
            mLed.updateLightsLocked();

            // This needs to be done after sendIntent() so that we get the lastest battery stats.
            if (logOutlier && dischargeDuration != 0) {
                logOutlierLocked(dischargeDuration);
            }

            mLastBatteryStatus = mHealthInfo.legacy.batteryStatus;
            mLastBatteryHealth = mHealthInfo.legacy.batteryHealth;
            mLastBatteryPresent = mHealthInfo.legacy.batteryPresent;
            mLastBatteryLevel = mHealthInfo.legacy.batteryLevel;
            mLastPlugType = mPlugType;
            mLastBatteryVoltage = mHealthInfo.legacy.batteryVoltage;
            mLastBatteryTemperature = mHealthInfo.legacy.batteryTemperature;
            mLastMaxChargingCurrent = mHealthInfo.legacy.maxChargingCurrent;
            mLastMaxChargingVoltage = mHealthInfo.legacy.maxChargingVoltage;
            mLastChargeCounter = mHealthInfo.legacy.batteryChargeCounter;
            mLastBatteryLevelCritical = mBatteryLevelCritical;
            mLastInvalidCharger = mInvalidCharger;
        }
    }

    private void sendIntentLocked() {
        //  Pack up the values and broadcast them to everyone
        final Intent intent = new Intent(Intent.ACTION_BATTERY_CHANGED);
        intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY
                | Intent.FLAG_RECEIVER_REPLACE_PENDING);

        int icon = getIconLocked(mHealthInfo.legacy.batteryLevel);

        intent.putExtra(BatteryManager.EXTRA_SEQUENCE, mSequence);
        intent.putExtra(BatteryManager.EXTRA_STATUS, mHealthInfo.legacy.batteryStatus);
        intent.putExtra(BatteryManager.EXTRA_HEALTH, mHealthInfo.legacy.batteryHealth);
        intent.putExtra(BatteryManager.EXTRA_PRESENT, mHealthInfo.legacy.batteryPresent);
        intent.putExtra(BatteryManager.EXTRA_LEVEL, mHealthInfo.legacy.batteryLevel);
        intent.putExtra(BatteryManager.EXTRA_SCALE, BATTERY_SCALE);
        intent.putExtra(BatteryManager.EXTRA_ICON_SMALL, icon);
        intent.putExtra(BatteryManager.EXTRA_PLUGGED, mPlugType);
        intent.putExtra(BatteryManager.EXTRA_VOLTAGE, mHealthInfo.legacy.batteryVoltage);
        intent.putExtra(BatteryManager.EXTRA_TEMPERATURE, mHealthInfo.legacy.batteryTemperature);
        intent.putExtra(BatteryManager.EXTRA_TECHNOLOGY, mHealthInfo.legacy.batteryTechnology);
        intent.putExtra(BatteryManager.EXTRA_INVALID_CHARGER, mInvalidCharger);
        intent.putExtra(BatteryManager.EXTRA_MAX_CHARGING_CURRENT, mHealthInfo.legacy.maxChargingCurrent);
        intent.putExtra(BatteryManager.EXTRA_MAX_CHARGING_VOLTAGE, mHealthInfo.legacy.maxChargingVoltage);
        intent.putExtra(BatteryManager.EXTRA_CHARGE_COUNTER, mHealthInfo.legacy.batteryChargeCounter);
        if (DEBUG) {
            Slog.d(TAG, "Sending ACTION_BATTERY_CHANGED. scale:" + BATTERY_SCALE
                    + ", info:" + mHealthInfo.toString());
        }

        mHandler.post(new Runnable() {
            @Override
            public void run() {
                ActivityManager.broadcastStickyIntent(intent, UserHandle.USER_ALL);
            }
        });
    }

    private void logBatteryStatsLocked() {
        IBinder batteryInfoService = ServiceManager.getService(BatteryStats.SERVICE_NAME);
        if (batteryInfoService == null) return;

        DropBoxManager db = (DropBoxManager) mContext.getSystemService(Context.DROPBOX_SERVICE);
        if (db == null || !db.isTagEnabled("BATTERY_DISCHARGE_INFO")) return;

        File dumpFile = null;
        FileOutputStream dumpStream = null;
        try {
            // dump the service to a file
            dumpFile = new File(DUMPSYS_DATA_PATH + BatteryStats.SERVICE_NAME + ".dump");
            dumpStream = new FileOutputStream(dumpFile);
            batteryInfoService.dump(dumpStream.getFD(), DUMPSYS_ARGS);
            FileUtils.sync(dumpStream);

            // add dump file to drop box
            db.addFile("BATTERY_DISCHARGE_INFO", dumpFile, DropBoxManager.IS_TEXT);
        } catch (RemoteException e) {
            Slog.e(TAG, "failed to dump battery service", e);
        } catch (IOException e) {
            Slog.e(TAG, "failed to write dumpsys file", e);
        } finally {
            // make sure we clean up
            if (dumpStream != null) {
                try {
                    dumpStream.close();
                } catch (IOException e) {
                    Slog.e(TAG, "failed to close dumpsys output stream");
                }
            }
            if (dumpFile != null && !dumpFile.delete()) {
                Slog.e(TAG, "failed to delete temporary dumpsys file: "
                        + dumpFile.getAbsolutePath());
            }
        }
    }

    private void logOutlierLocked(long duration) {
        ContentResolver cr = mContext.getContentResolver();
        String dischargeThresholdString = Settings.Global.getString(cr,
                Settings.Global.BATTERY_DISCHARGE_THRESHOLD);
        String durationThresholdString = Settings.Global.getString(cr,
                Settings.Global.BATTERY_DISCHARGE_DURATION_THRESHOLD);

        if (dischargeThresholdString != null && durationThresholdString != null) {
            try {
                long durationThreshold = Long.parseLong(durationThresholdString);
                int dischargeThreshold = Integer.parseInt(dischargeThresholdString);
                if (duration <= durationThreshold &&
                        mDischargeStartLevel - mHealthInfo.legacy.batteryLevel >= dischargeThreshold) {
                    // If the discharge cycle is bad enough we want to know about it.
                    logBatteryStatsLocked();
                }
                if (DEBUG) Slog.v(TAG, "duration threshold: " + durationThreshold +
                        " discharge threshold: " + dischargeThreshold);
                if (DEBUG) Slog.v(TAG, "duration: " + duration + " discharge: " +
                        (mDischargeStartLevel - mHealthInfo.legacy.batteryLevel));
            } catch (NumberFormatException e) {
                Slog.e(TAG, "Invalid DischargeThresholds GService string: " +
                        durationThresholdString + " or " + dischargeThresholdString);
            }
        }
    }

    private int getIconLocked(int level) {
        if (mHealthInfo.legacy.batteryStatus == BatteryManager.BATTERY_STATUS_CHARGING) {
            return com.android.internal.R.drawable.stat_sys_battery_charge;
        } else if (mHealthInfo.legacy.batteryStatus == BatteryManager.BATTERY_STATUS_DISCHARGING) {
            return com.android.internal.R.drawable.stat_sys_battery;
        } else if (mHealthInfo.legacy.batteryStatus == BatteryManager.BATTERY_STATUS_NOT_CHARGING
                || mHealthInfo.legacy.batteryStatus == BatteryManager.BATTERY_STATUS_FULL) {
            if (isPoweredLocked(BatteryManager.BATTERY_PLUGGED_ANY)
                    && mHealthInfo.legacy.batteryLevel >= 100) {
                return com.android.internal.R.drawable.stat_sys_battery_charge;
            } else {
                return com.android.internal.R.drawable.stat_sys_battery;
            }
        } else {
            return com.android.internal.R.drawable.stat_sys_battery_unknown;
        }
    }

    class Shell extends ShellCommand {
        @Override
        public int onCommand(String cmd) {
            return onShellCommand(this, cmd);
        }

        @Override
        public void onHelp() {
            PrintWriter pw = getOutPrintWriter();
            dumpHelp(pw);
        }
    }

    static void dumpHelp(PrintWriter pw) {
        pw.println("Battery service (battery) commands:");
        pw.println("  help");
        pw.println("    Print this help text.");
        pw.println("  set [-f] [ac|usb|wireless|status|level|temp|present|invalid] <value>");
        pw.println("    Force a battery property value, freezing battery state.");
        pw.println("    -f: force a battery change broadcast be sent, prints new sequence.");
        pw.println("  unplug [-f]");
        pw.println("    Force battery unplugged, freezing battery state.");
        pw.println("    -f: force a battery change broadcast be sent, prints new sequence.");
        pw.println("  reset [-f]");
        pw.println("    Unfreeze battery state, returning to current hardware values.");
        pw.println("    -f: force a battery change broadcast be sent, prints new sequence.");
    }

    static final int OPTION_FORCE_UPDATE = 1<<0;

    int parseOptions(Shell shell) {
        String opt;
        int opts = 0;
        while ((opt = shell.getNextOption()) != null) {
            if ("-f".equals(opt)) {
                opts |= OPTION_FORCE_UPDATE;
            }
        }
        return opts;
    }

    int onShellCommand(Shell shell, String cmd) {
        if (cmd == null) {
            return shell.handleDefaultCommands(cmd);
        }
        PrintWriter pw = shell.getOutPrintWriter();
        switch (cmd) {
            case "unplug": {
                int opts = parseOptions(shell);
                getContext().enforceCallingOrSelfPermission(
                        android.Manifest.permission.DEVICE_POWER, null);
                if (!mUpdatesStopped) {
                    copy(mLastHealthInfo, mHealthInfo);
                }
                mHealthInfo.legacy.chargerAcOnline = false;
                mHealthInfo.legacy.chargerUsbOnline = false;
                mHealthInfo.legacy.chargerWirelessOnline = false;
                long ident = Binder.clearCallingIdentity();
                try {
                    mUpdatesStopped = true;
                    processValuesFromShellLocked(pw, opts);
                } finally {
                    Binder.restoreCallingIdentity(ident);
                }
            } break;
            case "set": {
                int opts = parseOptions(shell);
                getContext().enforceCallingOrSelfPermission(
                        android.Manifest.permission.DEVICE_POWER, null);
                final String key = shell.getNextArg();
                if (key == null) {
                    pw.println("No property specified");
                    return -1;

                }
                final String value = shell.getNextArg();
                if (value == null) {
                    pw.println("No value specified");
                    return -1;

                }
                try {
                    if (!mUpdatesStopped) {
                        copy(mLastHealthInfo, mHealthInfo);
                    }
                    boolean update = true;
                    switch (key) {
                        case "present":
                            mHealthInfo.legacy.batteryPresent = Integer.parseInt(value) != 0;
                            break;
                        case "ac":
                            mHealthInfo.legacy.chargerAcOnline = Integer.parseInt(value) != 0;
                            break;
                        case "usb":
                            mHealthInfo.legacy.chargerUsbOnline = Integer.parseInt(value) != 0;
                            break;
                        case "wireless":
                            mHealthInfo.legacy.chargerWirelessOnline = Integer.parseInt(value) != 0;
                            break;
                        case "status":
                            mHealthInfo.legacy.batteryStatus = Integer.parseInt(value);
                            break;
                        case "level":
                            mHealthInfo.legacy.batteryLevel = Integer.parseInt(value);
                            break;
                        case "temp":
                            mHealthInfo.legacy.batteryTemperature = Integer.parseInt(value);
                            break;
                        case "invalid":
                            mInvalidCharger = Integer.parseInt(value);
                            break;
                        default:
                            pw.println("Unknown set option: " + key);
                            update = false;
                            break;
                    }
                    if (update) {
                        long ident = Binder.clearCallingIdentity();
                        try {
                            mUpdatesStopped = true;
                            processValuesFromShellLocked(pw, opts);
                        } finally {
                            Binder.restoreCallingIdentity(ident);
                        }
                    }
                } catch (NumberFormatException ex) {
                    pw.println("Bad value: " + value);
                    return -1;
                }
            } break;
            case "reset": {
                int opts = parseOptions(shell);
                getContext().enforceCallingOrSelfPermission(
                        android.Manifest.permission.DEVICE_POWER, null);
                long ident = Binder.clearCallingIdentity();
                try {
                    if (mUpdatesStopped) {
                        mUpdatesStopped = false;
                        copy(mHealthInfo, mLastHealthInfo);
                        processValuesFromShellLocked(pw, opts);
                    }
                } finally {
                    Binder.restoreCallingIdentity(ident);
                }
            } break;
            default:
                return shell.handleDefaultCommands(cmd);
        }
        return 0;
    }

    private void processValuesFromShellLocked(PrintWriter pw, int opts) {
        processValuesLocked((opts & OPTION_FORCE_UPDATE) != 0);
        if ((opts & OPTION_FORCE_UPDATE) != 0) {
            pw.println(mSequence);
        }
    }

    private void dumpInternal(FileDescriptor fd, PrintWriter pw, String[] args) {
        synchronized (mLock) {
            if (args == null || args.length == 0 || "-a".equals(args[0])) {
                pw.println("Current Battery Service state:");
                if (mUpdatesStopped) {
                    pw.println("  (UPDATES STOPPED -- use 'reset' to restart)");
                }
                pw.println("  AC powered: " + mHealthInfo.legacy.chargerAcOnline);
                pw.println("  USB powered: " + mHealthInfo.legacy.chargerUsbOnline);
                pw.println("  Wireless powered: " + mHealthInfo.legacy.chargerWirelessOnline);
                pw.println("  Max charging current: " + mHealthInfo.legacy.maxChargingCurrent);
                pw.println("  Max charging voltage: " + mHealthInfo.legacy.maxChargingVoltage);
                pw.println("  Charge counter: " + mHealthInfo.legacy.batteryChargeCounter);
                pw.println("  status: " + mHealthInfo.legacy.batteryStatus);
                pw.println("  health: " + mHealthInfo.legacy.batteryHealth);
                pw.println("  present: " + mHealthInfo.legacy.batteryPresent);
                pw.println("  level: " + mHealthInfo.legacy.batteryLevel);
                pw.println("  scale: " + BATTERY_SCALE);
                pw.println("  voltage: " + mHealthInfo.legacy.batteryVoltage);
                pw.println("  temperature: " + mHealthInfo.legacy.batteryTemperature);
                pw.println("  technology: " + mHealthInfo.legacy.batteryTechnology);
            } else {
                Shell shell = new Shell();
                shell.exec(mBinderService, null, fd, null, args, null, new ResultReceiver(null));
            }
        }
    }

    private void dumpProto(FileDescriptor fd) {
        final ProtoOutputStream proto = new ProtoOutputStream(fd);

        synchronized (mLock) {
            proto.write(BatteryServiceDumpProto.ARE_UPDATES_STOPPED, mUpdatesStopped);
            int batteryPluggedValue = BatteryManagerProto.PLUG_TYPE_NONE;
            if (mHealthInfo.legacy.chargerAcOnline) {
                batteryPluggedValue = BatteryManagerProto.PLUG_TYPE_AC;
            } else if (mHealthInfo.legacy.chargerUsbOnline) {
                batteryPluggedValue = BatteryManagerProto.PLUG_TYPE_USB;
            } else if (mHealthInfo.legacy.chargerWirelessOnline) {
                batteryPluggedValue = BatteryManagerProto.PLUG_TYPE_WIRELESS;
            }
            proto.write(BatteryServiceDumpProto.PLUGGED, batteryPluggedValue);
            proto.write(BatteryServiceDumpProto.MAX_CHARGING_CURRENT, mHealthInfo.legacy.maxChargingCurrent);
            proto.write(BatteryServiceDumpProto.MAX_CHARGING_VOLTAGE, mHealthInfo.legacy.maxChargingVoltage);
            proto.write(BatteryServiceDumpProto.CHARGE_COUNTER, mHealthInfo.legacy.batteryChargeCounter);
            proto.write(BatteryServiceDumpProto.STATUS, mHealthInfo.legacy.batteryStatus);
            proto.write(BatteryServiceDumpProto.HEALTH, mHealthInfo.legacy.batteryHealth);
            proto.write(BatteryServiceDumpProto.IS_PRESENT, mHealthInfo.legacy.batteryPresent);
            proto.write(BatteryServiceDumpProto.LEVEL, mHealthInfo.legacy.batteryLevel);
            proto.write(BatteryServiceDumpProto.SCALE, BATTERY_SCALE);
            proto.write(BatteryServiceDumpProto.VOLTAGE, mHealthInfo.legacy.batteryVoltage);
            proto.write(BatteryServiceDumpProto.TEMPERATURE, mHealthInfo.legacy.batteryTemperature);
            proto.write(BatteryServiceDumpProto.TECHNOLOGY, mHealthInfo.legacy.batteryTechnology);
        }
        proto.flush();
    }

    private final class Led {
        private final Light mBatteryLight;

        private final int mBatteryLowARGB;
        private final int mBatteryMediumARGB;
        private final int mBatteryFullARGB;
        private final int mBatteryLedOn;
        private final int mBatteryLedOff;

        public Led(Context context, LightsManager lights) {
            mBatteryLight = lights.getLight(LightsManager.LIGHT_ID_BATTERY);

            mBatteryLowARGB = context.getResources().getInteger(
                    com.android.internal.R.integer.config_notificationsBatteryLowARGB);
            mBatteryMediumARGB = context.getResources().getInteger(
                    com.android.internal.R.integer.config_notificationsBatteryMediumARGB);
            mBatteryFullARGB = context.getResources().getInteger(
                    com.android.internal.R.integer.config_notificationsBatteryFullARGB);
            mBatteryLedOn = context.getResources().getInteger(
                    com.android.internal.R.integer.config_notificationsBatteryLedOn);
            mBatteryLedOff = context.getResources().getInteger(
                    com.android.internal.R.integer.config_notificationsBatteryLedOff);
        }

        /**
         * Synchronize on BatteryService.
         */
        public void updateLightsLocked() {
            final int level = mHealthInfo.legacy.batteryLevel;
            final int status = mHealthInfo.legacy.batteryStatus;
            if (level < mLowBatteryWarningLevel) {
                if (status == BatteryManager.BATTERY_STATUS_CHARGING) {
                    // Solid red when battery is charging
                    mBatteryLight.setColor(mBatteryLowARGB);
                } else {
                    // Flash red when battery is low and not charging
                    mBatteryLight.setFlashing(mBatteryLowARGB, Light.LIGHT_FLASH_TIMED,
                            mBatteryLedOn, mBatteryLedOff);
                }
            } else if (status == BatteryManager.BATTERY_STATUS_CHARGING
                    || status == BatteryManager.BATTERY_STATUS_FULL) {
                if (status == BatteryManager.BATTERY_STATUS_FULL || level >= 90) {
                    // Solid green when full or charging and nearly full
                    mBatteryLight.setColor(mBatteryFullARGB);
                } else {
                    // Solid orange when charging and halfway full
                    mBatteryLight.setColor(mBatteryMediumARGB);
                }
            } else {
                // No lights if not charging and not low
                mBatteryLight.turnOff();
            }
        }
    }

    private final class HealthHalCallback extends IHealthInfoCallback.Stub
            implements HealthServiceWrapper.Callback {
        @Override public void healthInfoChanged(HealthInfo props) {
            BatteryService.this.update(props);
        }
        // on new service registered
        @Override public void onRegistration(IHealth oldService, IHealth newService,
                String instance) {
            if (newService == null) return;

            try {
                if (oldService != null) {
                    int r = oldService.unregisterCallback(this);
                    if (r != Result.SUCCESS) {
                        Slog.w(TAG, "health: cannot unregister previous callback: " +
                                Result.toString(r));
                    }
                }
            } catch (RemoteException ex) {
                Slog.w(TAG, "health: cannot unregister previous callback (transaction error): "
                            + ex.getMessage());
            }

            try {
                int r = newService.registerCallback(this);
                if (r != Result.SUCCESS) {
                    Slog.w(TAG, "health: cannot register callback: " + Result.toString(r));
                    return;
                }
                // registerCallback does NOT guarantee that update is called
                // immediately, so request a manual update here.
                newService.update();
            } catch (RemoteException ex) {
                Slog.e(TAG, "health: cannot register callback (transaction error): "
                        + ex.getMessage());
            }
        }
    }

    private final class BinderService extends Binder {
        @Override protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
            if (!DumpUtils.checkDumpPermission(mContext, TAG, pw)) return;

            if (args.length > 0 && "--proto".equals(args[0])) {
                dumpProto(fd);
            } else {
                dumpInternal(fd, pw, args);
            }
        }

        @Override public void onShellCommand(FileDescriptor in, FileDescriptor out,
                FileDescriptor err, String[] args, ShellCallback callback,
                ResultReceiver resultReceiver) {
            (new Shell()).exec(this, in, out, err, args, callback, resultReceiver);
        }
    }

    // Reduced IBatteryPropertiesRegistrar that only implements getProperty for usage
    // in BatteryManager.
    private final class BatteryPropertiesRegistrar extends IBatteryPropertiesRegistrar.Stub {
        public void registerListener(IBatteryPropertiesListener listener) {
            Slog.e(TAG, "health: must not call registerListener on battery properties");
        }
        public void unregisterListener(IBatteryPropertiesListener listener) {
            Slog.e(TAG, "health: must not call unregisterListener on battery properties");
        }
        public int getProperty(int id, final BatteryProperty prop) throws RemoteException {
            IHealth service = mHealthServiceWrapper.getLastService();
            if (service == null) throw new RemoteException("no health service");
            final MutableInt outResult = new MutableInt(Result.NOT_SUPPORTED);
            switch(id) {
                case BatteryManager.BATTERY_PROPERTY_CHARGE_COUNTER:
                    service.getChargeCounter((int result, int value) -> {
                        outResult.value = result;
                        if (result == Result.SUCCESS) prop.setLong(value);
                    });
                    break;
                case BatteryManager.BATTERY_PROPERTY_CURRENT_NOW:
                    service.getCurrentNow((int result, int value) -> {
                        outResult.value = result;
                        if (result == Result.SUCCESS) prop.setLong(value);
                    });
                    break;
                case BatteryManager.BATTERY_PROPERTY_CURRENT_AVERAGE:
                    service.getCurrentAverage((int result, int value) -> {
                        outResult.value = result;
                        if (result == Result.SUCCESS) prop.setLong(value);
                    });
                    break;
                case BatteryManager.BATTERY_PROPERTY_CAPACITY:
                    service.getCapacity((int result, int value) -> {
                        outResult.value = result;
                        if (result == Result.SUCCESS) prop.setLong(value);
                    });
                    break;
                case BatteryManager.BATTERY_PROPERTY_STATUS:
                    service.getChargeStatus((int result, int value) -> {
                        outResult.value = result;
                        if (result == Result.SUCCESS) prop.setLong(value);
                    });
                    break;
                case BatteryManager.BATTERY_PROPERTY_ENERGY_COUNTER:
                    service.getEnergyCounter((int result, long value) -> {
                        outResult.value = result;
                        if (result == Result.SUCCESS) prop.setLong(value);
                    });
                    break;
            }
            return outResult.value;
        }
        public void scheduleUpdate() throws RemoteException {
            IHealth service = mHealthServiceWrapper.getLastService();
            if (service == null) throw new RemoteException("no health service");
            service.update();
        }
    }

    private final class LocalService extends BatteryManagerInternal {
        @Override
        public boolean isPowered(int plugTypeSet) {
            synchronized (mLock) {
                return isPoweredLocked(plugTypeSet);
            }
        }

        @Override
        public int getPlugType() {
            synchronized (mLock) {
                return mPlugType;
            }
        }

        @Override
        public int getBatteryLevel() {
            synchronized (mLock) {
                return mHealthInfo.legacy.batteryLevel;
            }
        }

        @Override
        public boolean getBatteryLevelLow() {
            synchronized (mLock) {
                return mBatteryLevelLow;
            }
        }

        @Override
        public int getInvalidCharger() {
            synchronized (mLock) {
                return mInvalidCharger;
            }
        }
    }

    /**
     * HealthServiceWrapper wraps the internal IHealth service and refreshes the service when
     * necessary.
     *
     * On new registration of IHealth service, {@link #onRegistration onRegistration} is called and
     * the internal service is refreshed.
     * On death of an existing IHealth service, the internal service is NOT cleared to avoid
     * race condition between death notification and new service notification. Hence,
     * a caller must check for transaction errors when calling into the service.
     *
     * @hide Should only be used internally.
     */
    @VisibleForTesting
    static final class HealthServiceWrapper {
        private static final String TAG = "HealthServiceWrapper";
        public static final String INSTANCE_HEALTHD = "backup";
        public static final String INSTANCE_VENDOR = "default";
        // All interesting instances, sorted by priority high -> low.
        private static final List<String> sAllInstances =
                Arrays.asList(INSTANCE_VENDOR, INSTANCE_HEALTHD);

        private final IServiceNotification mNotification = new Notification();
        private Callback mCallback;
        private IHealthSupplier mHealthSupplier;

        private final Object mLastServiceSetLock = new Object();
        // Last IHealth service received.
        // set must be also be guarded with mLastServiceSetLock to ensure ordering.
        private final AtomicReference<IHealth> mLastService = new AtomicReference<>();

        /**
         * init should be called after constructor. For testing purposes, init is not called by
         * constructor.
         */
        HealthServiceWrapper() {
        }

        IHealth getLastService() {
            return mLastService.get();
        }

        /**
         * Start monitoring registration of new IHealth services. Only instances that are in
         * {@code sAllInstances} and in device / framework manifest are used. This function should
         * only be called once.
         * @throws RemoteException transaction error when talking to IServiceManager
         * @throws NoSuchElementException if one of the following cases:
         *         - No service manager;
         *         - none of {@code sAllInstances} are in manifests (i.e. not
         *           available on this device), or none of these instances are available to current
         *           process.
         * @throws NullPointerException when callback is null or supplier is null
         */
        void init(Callback callback,
                  IServiceManagerSupplier managerSupplier,
                  IHealthSupplier healthSupplier)
                throws RemoteException, NoSuchElementException, NullPointerException {
            if (callback == null || managerSupplier == null || healthSupplier == null)
                throw new NullPointerException();

            mCallback = callback;
            mHealthSupplier = healthSupplier;

            IServiceManager manager = managerSupplier.get();
            for (String name : sAllInstances) {
                if (manager.getTransport(IHealth.kInterfaceName, name) ==
                        IServiceManager.Transport.EMPTY) {
                    continue;
                }

                manager.registerForNotifications(IHealth.kInterfaceName, name, mNotification);
                Slog.i(TAG, "health: HealthServiceWrapper listening to instance " + name);
                return;
            }

            throw new NoSuchElementException(String.format(
                    "No IHealth service instance among %s is available. Perhaps no permission?",
                    sAllInstances.toString()));
        }

        interface Callback {
            /**
             * This function is invoked asynchronously when a new and related IServiceNotification
             * is received.
             * @param service the recently retrieved service from IServiceManager.
             * Can be a dead service before service notification of a new service is delivered.
             * Implementation must handle cases for {@link RemoteException}s when calling
             * into service.
             * @param instance instance name.
             */
            void onRegistration(IHealth oldService, IHealth newService, String instance);
        }

        /**
         * Supplier of services.
         * Must not return null; throw {@link NoSuchElementException} if a service is not available.
         */
        interface IServiceManagerSupplier {
            default IServiceManager get() throws NoSuchElementException, RemoteException {
                return IServiceManager.getService();
            }
        }
        /**
         * Supplier of services.
         * Must not return null; throw {@link NoSuchElementException} if a service is not available.
         */
        interface IHealthSupplier {
            default IHealth get(String name) throws NoSuchElementException, RemoteException {
                return IHealth.getService(name);
            }
        }

        private class Notification extends IServiceNotification.Stub {
            @Override
            public final void onRegistration(String interfaceName, String instanceName,
                    boolean preexisting) {
                if (!IHealth.kInterfaceName.equals(interfaceName)) return;
                if (!sAllInstances.contains(instanceName)) return;
                try {
                    // ensures the order of multiple onRegistration on different threads.
                    synchronized (mLastServiceSetLock) {
                        IHealth newService = mHealthSupplier.get(instanceName);
                        IHealth oldService = mLastService.getAndSet(newService);
                        Slog.i(TAG, "health: new instance registered " + instanceName);
                        mCallback.onRegistration(oldService, newService, instanceName);
                    }
                } catch (NoSuchElementException | RemoteException ex) {
                    Slog.e(TAG, "health: Cannot get instance '" + instanceName + "': " +
                           ex.getMessage() + ". Perhaps no permission?");
                }
            }
        }
    }
}