server/notification/RankingHelper.java

/**
 * Copyright (c) 2014, 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.notification;

import static android.app.NotificationManager.IMPORTANCE_NONE;

import com.android.internal.R;
import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.util.Preconditions;

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationChannelGroup;
import android.app.NotificationManager;
import android.content.Context;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.pm.ParceledListSlice;
import android.os.Build;
import android.os.UserHandle;
import android.service.notification.NotificationListenerService.Ranking;
import android.text.TextUtils;
import android.util.ArrayMap;
import android.util.Slog;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlSerializer;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

public class RankingHelper implements RankingConfig {
    private static final String TAG = "RankingHelper";

    private static final int XML_VERSION = 1;

    private static final String TAG_RANKING = "ranking";
    private static final String TAG_PACKAGE = "package";
    private static final String TAG_CHANNEL = "channel";
    private static final String TAG_GROUP = "channelGroup";

    private static final String ATT_VERSION = "version";
    private static final String ATT_NAME = "name";
    private static final String ATT_UID = "uid";
    private static final String ATT_ID = "id";
    private static final String ATT_PRIORITY = "priority";
    private static final String ATT_VISIBILITY = "visibility";
    private static final String ATT_IMPORTANCE = "importance";
    private static final String ATT_SHOW_BADGE = "show_badge";

    private static final int DEFAULT_PRIORITY = Notification.PRIORITY_DEFAULT;
    private static final int DEFAULT_VISIBILITY = NotificationManager.VISIBILITY_NO_OVERRIDE;
    private static final int DEFAULT_IMPORTANCE = NotificationManager.IMPORTANCE_UNSPECIFIED;
    private static final boolean DEFAULT_SHOW_BADGE = true;

    private final NotificationSignalExtractor[] mSignalExtractors;
    private final NotificationComparator mPreliminaryComparator;
    private final GlobalSortKeyComparator mFinalComparator = new GlobalSortKeyComparator();

    private final ArrayMap<String, Record> mRecords = new ArrayMap<>(); // pkg|uid => Record
    private final ArrayMap<String, NotificationRecord> mProxyByGroupTmp = new ArrayMap<>();
    private final ArrayMap<String, Record> mRestoredWithoutUids = new ArrayMap<>(); // pkg => Record

    private final Context mContext;
    private final RankingHandler mRankingHandler;
    private final PackageManager mPm;

    public RankingHelper(Context context, PackageManager pm, RankingHandler rankingHandler,
            NotificationUsageStats usageStats, String[] extractorNames) {
        mContext = context;
        mRankingHandler = rankingHandler;
        mPm = pm;

        mPreliminaryComparator = new NotificationComparator(mContext);

        final int N = extractorNames.length;
        mSignalExtractors = new NotificationSignalExtractor[N];
        for (int i = 0; i < N; i++) {
            try {
                Class<?> extractorClass = mContext.getClassLoader().loadClass(extractorNames[i]);
                NotificationSignalExtractor extractor =
                        (NotificationSignalExtractor) extractorClass.newInstance();
                extractor.initialize(mContext, usageStats);
                extractor.setConfig(this);
                mSignalExtractors[i] = extractor;
            } catch (ClassNotFoundException e) {
                Slog.w(TAG, "Couldn't find extractor " + extractorNames[i] + ".", e);
            } catch (InstantiationException e) {
                Slog.w(TAG, "Couldn't instantiate extractor " + extractorNames[i] + ".", e);
            } catch (IllegalAccessException e) {
                Slog.w(TAG, "Problem accessing extractor " + extractorNames[i] + ".", e);
            }
        }
    }

    @SuppressWarnings("unchecked")
    public <T extends NotificationSignalExtractor> T findExtractor(Class<T> extractorClass) {
        final int N = mSignalExtractors.length;
        for (int i = 0; i < N; i++) {
            final NotificationSignalExtractor extractor = mSignalExtractors[i];
            if (extractorClass.equals(extractor.getClass())) {
                return (T) extractor;
            }
        }
        return null;
    }

    public void extractSignals(NotificationRecord r) {
        final int N = mSignalExtractors.length;
        for (int i = 0; i < N; i++) {
            NotificationSignalExtractor extractor = mSignalExtractors[i];
            try {
                RankingReconsideration recon = extractor.process(r);
                if (recon != null) {
                    mRankingHandler.requestReconsideration(recon);
                }
            } catch (Throwable t) {
                Slog.w(TAG, "NotificationSignalExtractor failed.", t);
            }
        }
    }

    public void readXml(XmlPullParser parser, boolean forRestore)
            throws XmlPullParserException, IOException {
        int type = parser.getEventType();
        if (type != XmlPullParser.START_TAG) return;
        String tag = parser.getName();
        if (!TAG_RANKING.equals(tag)) return;
        mRecords.clear();
        mRestoredWithoutUids.clear();
        while ((type = parser.next()) != XmlPullParser.END_DOCUMENT) {
            tag = parser.getName();
            if (type == XmlPullParser.END_TAG && TAG_RANKING.equals(tag)) {
                return;
            }
            if (type == XmlPullParser.START_TAG) {
                if (TAG_PACKAGE.equals(tag)) {
                    int uid = safeInt(parser, ATT_UID, Record.UNKNOWN_UID);
                    String name = parser.getAttributeValue(null, ATT_NAME);
                    if (!TextUtils.isEmpty(name)) {
                        if (forRestore) {
                            try {
                                //TODO: http://b/22388012
                                uid = mPm.getPackageUidAsUser(name, UserHandle.USER_SYSTEM);
                            } catch (NameNotFoundException e) {
                                // noop
                            }
                        }

                        Record r = getOrCreateRecord(name, uid,
                                safeInt(parser, ATT_IMPORTANCE, DEFAULT_IMPORTANCE),
                                safeInt(parser, ATT_PRIORITY, DEFAULT_PRIORITY),
                                safeInt(parser, ATT_VISIBILITY, DEFAULT_VISIBILITY),
                                safeBool(parser, ATT_SHOW_BADGE, DEFAULT_SHOW_BADGE));

                        final int innerDepth = parser.getDepth();
                        while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
                                && (type != XmlPullParser.END_TAG
                                || parser.getDepth() > innerDepth)) {
                            if (type == XmlPullParser.END_TAG || type == XmlPullParser.TEXT) {
                                continue;
                            }

                            String tagName = parser.getName();
                            // Channel groups
                            if (TAG_GROUP.equals(tagName)) {
                                String id = parser.getAttributeValue(null, ATT_ID);
                                CharSequence groupName = parser.getAttributeValue(null, ATT_NAME);
                                if (!TextUtils.isEmpty(id)) {
                                    final NotificationChannelGroup group =
                                            new NotificationChannelGroup(id, groupName);
                                    r.groups.put(id, group);
                                }
                            }
                            // Channels
                            if (TAG_CHANNEL.equals(tagName)) {
                                String id = parser.getAttributeValue(null, ATT_ID);
                                CharSequence channelName = parser.getAttributeValue(null, ATT_NAME);
                                int channelImportance =
                                        safeInt(parser, ATT_IMPORTANCE, DEFAULT_IMPORTANCE);

                                if (!TextUtils.isEmpty(id)) {
                                    final NotificationChannel channel = new NotificationChannel(id,
                                            channelName, channelImportance);
                                    channel.populateFromXml(parser);
                                    r.channels.put(id, channel);
                                }
                            }
                        }

                        clampDefaultChannel(r);
                    }
                }
            }
        }
        throw new IllegalStateException("Failed to reach END_DOCUMENT");
    }

    private static String recordKey(String pkg, int uid) {
        return pkg + "|" + uid;
    }

    private Record getRecord(String pkg, int uid) {
        final String key = recordKey(pkg, uid);
        return mRecords.get(key);
    }

    private Record getOrCreateRecord(String pkg, int uid) {
        return getOrCreateRecord(pkg, uid,
                DEFAULT_IMPORTANCE, DEFAULT_PRIORITY, DEFAULT_VISIBILITY, DEFAULT_SHOW_BADGE);
    }

    private Record getOrCreateRecord(String pkg, int uid, int importance, int priority,
            int visibility, boolean showBadge) {
        final String key = recordKey(pkg, uid);
        Record r = (uid == Record.UNKNOWN_UID) ? mRestoredWithoutUids.get(pkg) : mRecords.get(key);
        if (r == null) {
            r = new Record();
            r.pkg = pkg;
            r.uid = uid;
            r.importance = importance;
            r.priority = priority;
            r.visibility = visibility;
            r.showBadge = showBadge;
            createDefaultChannelIfMissing(r);
            if (r.uid == Record.UNKNOWN_UID) {
                mRestoredWithoutUids.put(pkg, r);
            } else {
                mRecords.put(key, r);
            }
            clampDefaultChannel(r);
        }
        return r;
    }

    // Clamp the importance level of the default channel for apps targeting the new SDK version,
    // unless the user has already changed the importance.
    private void clampDefaultChannel(Record r) {
        try {
            if (r.uid != Record.UNKNOWN_UID) {
                int userId = UserHandle.getUserId(r.uid);
                final ApplicationInfo applicationInfo =
                        mPm.getApplicationInfoAsUser(r.pkg, 0, userId);
                if (applicationInfo.targetSdkVersion > Build.VERSION_CODES.N_MR1) {
                    final NotificationChannel defaultChannel =
                            r.channels.get(NotificationChannel.DEFAULT_CHANNEL_ID);
                    if ((defaultChannel.getUserLockedFields()
                            & NotificationChannel.USER_LOCKED_IMPORTANCE) == 0) {
                        defaultChannel.setImportance(NotificationManager.IMPORTANCE_LOW);
                        updateConfig();
                    }
                }
            }
        } catch (NameNotFoundException e) {
            // oh well.
        }
    }

    private void createDefaultChannelIfMissing(Record r) {
        if (!r.channels.containsKey(NotificationChannel.DEFAULT_CHANNEL_ID)) {
            NotificationChannel channel;
            channel = new NotificationChannel(
                    NotificationChannel.DEFAULT_CHANNEL_ID,
                    mContext.getString(R.string.default_notification_channel_label),
                    r.importance);
            channel.setBypassDnd(r.priority == Notification.PRIORITY_MAX);
            channel.setLockscreenVisibility(r.visibility);
            if (r.importance != NotificationManager.IMPORTANCE_UNSPECIFIED) {
                channel.lockFields(NotificationChannel.USER_LOCKED_IMPORTANCE);
            }
            if (r.priority != DEFAULT_PRIORITY) {
                channel.lockFields(NotificationChannel.USER_LOCKED_PRIORITY);
            }
            if (r.visibility != DEFAULT_VISIBILITY) {
                channel.lockFields(NotificationChannel.USER_LOCKED_VISIBILITY);
            }
            r.channels.put(channel.getId(), channel);
        }
    }

    public void writeXml(XmlSerializer out, boolean forBackup) throws IOException {
        out.startTag(null, TAG_RANKING);
        out.attribute(null, ATT_VERSION, Integer.toString(XML_VERSION));

        final int N = mRecords.size();
        for (int i = 0; i < N; i++) {
            final Record r = mRecords.valueAt(i);
            //TODO: http://b/22388012
            if (forBackup && UserHandle.getUserId(r.uid) != UserHandle.USER_SYSTEM) {
                continue;
            }
            final boolean hasNonDefaultSettings = r.importance != DEFAULT_IMPORTANCE
                    || r.priority != DEFAULT_PRIORITY || r.visibility != DEFAULT_VISIBILITY
                    || r.showBadge != DEFAULT_SHOW_BADGE || r.channels.size() > 0
                    || r.groups.size() > 0;
            if (hasNonDefaultSettings) {
                out.startTag(null, TAG_PACKAGE);
                out.attribute(null, ATT_NAME, r.pkg);
                if (r.importance != DEFAULT_IMPORTANCE) {
                    out.attribute(null, ATT_IMPORTANCE, Integer.toString(r.importance));
                }
                if (r.priority != DEFAULT_PRIORITY) {
                    out.attribute(null, ATT_PRIORITY, Integer.toString(r.priority));
                }
                if (r.visibility != DEFAULT_VISIBILITY) {
                    out.attribute(null, ATT_VISIBILITY, Integer.toString(r.visibility));
                }
                out.attribute(null, ATT_SHOW_BADGE, Boolean.toString(r.showBadge));

                if (!forBackup) {
                    out.attribute(null, ATT_UID, Integer.toString(r.uid));
                }

                for (NotificationChannelGroup group : r.groups.values()) {
                    group.writeXml(out);
                }

                for (NotificationChannel channel : r.channels.values()) {
                    channel.writeXml(out);
                }

                out.endTag(null, TAG_PACKAGE);
            }
        }
        out.endTag(null, TAG_RANKING);
    }

    private void updateConfig() {
        final int N = mSignalExtractors.length;
        for (int i = 0; i < N; i++) {
            mSignalExtractors[i].setConfig(this);
        }
        mRankingHandler.requestSort(false);
    }

    public void sort(ArrayList<NotificationRecord> notificationList) {
        final int N = notificationList.size();
        // clear global sort keys
        for (int i = N - 1; i >= 0; i--) {
            notificationList.get(i).setGlobalSortKey(null);
        }

        // rank each record individually
        Collections.sort(notificationList, mPreliminaryComparator);

        synchronized (mProxyByGroupTmp) {
            // record individual ranking result and nominate proxies for each group
            for (int i = N - 1; i >= 0; i--) {
                final NotificationRecord record = notificationList.get(i);
                record.setAuthoritativeRank(i);
                final String groupKey = record.getGroupKey();
                boolean isGroupSummary = record.getNotification().isGroupSummary();
                if (isGroupSummary || !mProxyByGroupTmp.containsKey(groupKey)) {
                    mProxyByGroupTmp.put(groupKey, record);
                }
            }
            // assign global sort key:
            //   is_recently_intrusive:group_rank:is_group_summary:group_sort_key:rank
            for (int i = 0; i < N; i++) {
                final NotificationRecord record = notificationList.get(i);
                NotificationRecord groupProxy = mProxyByGroupTmp.get(record.getGroupKey());
                String groupSortKey = record.getNotification().getSortKey();

                // We need to make sure the developer provided group sort key (gsk) is handled
                // correctly:
                //   gsk="" < gsk=non-null-string < gsk=null
                //
                // We enforce this by using different prefixes for these three cases.
                String groupSortKeyPortion;
                if (groupSortKey == null) {
                    groupSortKeyPortion = "nsk";
                } else if (groupSortKey.equals("")) {
                    groupSortKeyPortion = "esk";
                } else {
                    groupSortKeyPortion = "gsk=" + groupSortKey;
                }

                boolean isGroupSummary = record.getNotification().isGroupSummary();
                record.setGlobalSortKey(
                        String.format("intrsv=%c:grnk=0x%04x:gsmry=%c:%s:rnk=0x%04x",
                        record.isRecentlyIntrusive() ? '0' : '1',
                        groupProxy.getAuthoritativeRank(),
                        isGroupSummary ? '0' : '1',
                        groupSortKeyPortion,
                        record.getAuthoritativeRank()));
            }
            mProxyByGroupTmp.clear();
        }

        // Do a second ranking pass, using group proxies
        Collections.sort(notificationList, mFinalComparator);
    }

    public int indexOf(ArrayList<NotificationRecord> notificationList, NotificationRecord target) {
        return Collections.binarySearch(notificationList, target, mFinalComparator);
    }

    private static boolean safeBool(XmlPullParser parser, String att, boolean defValue) {
        final String value = parser.getAttributeValue(null, att);
        if (TextUtils.isEmpty(value)) return defValue;
        return Boolean.parseBoolean(value);
    }

    private static int safeInt(XmlPullParser parser, String att, int defValue) {
        final String val = parser.getAttributeValue(null, att);
        return tryParseInt(val, defValue);
    }

    private static int tryParseInt(String value, int defValue) {
        if (TextUtils.isEmpty(value)) return defValue;
        try {
            return Integer.parseInt(value);
        } catch (NumberFormatException e) {
            return defValue;
        }
    }

    /**
     * Gets importance.
     */
    @Override
    public int getImportance(String packageName, int uid) {
        return getOrCreateRecord(packageName, uid).importance;
    }

    @Override
    public boolean canShowBadge(String packageName, int uid) {
        return getOrCreateRecord(packageName, uid).showBadge;
    }

    @Override
    public void setShowBadge(String packageName, int uid, boolean showBadge) {
        getOrCreateRecord(packageName, uid).showBadge = showBadge;
        updateConfig();
    }

    @Override
    public void createNotificationChannelGroup(String pkg, int uid, NotificationChannelGroup group,
            boolean fromTargetApp) {
        Preconditions.checkNotNull(pkg);
        Preconditions.checkNotNull(group);
        Preconditions.checkNotNull(group.getId());
        Preconditions.checkNotNull(group.getName());
        Record r = getOrCreateRecord(pkg, uid);
        if (r == null) {
            throw new IllegalArgumentException("Invalid package");
        }
        r.groups.put(group.getId(), group);
        updateConfig();
    }

    @Override
    public void createNotificationChannel(String pkg, int uid, NotificationChannel channel,
            boolean fromTargetApp) {
        Preconditions.checkNotNull(pkg);
        Preconditions.checkNotNull(channel);
        Preconditions.checkNotNull(channel.getId());
        Preconditions.checkNotNull(channel.getName());
        Record r = getOrCreateRecord(pkg, uid);
        if (r == null) {
            throw new IllegalArgumentException("Invalid package");
        }
        if (IMPORTANCE_NONE == r.importance) {
            throw new IllegalArgumentException("Package blocked");
        }
        if (channel.getGroup() != null && !r.groups.containsKey(channel.getGroup())) {
            throw new IllegalArgumentException("NotificationChannelGroup doesn't exist");
        }

        NotificationChannel existing = r.channels.get(channel.getId());
        // Keep existing settings
        if (existing != null) {
            if (existing.isDeleted()) {
                existing.setDeleted(false);
                updateConfig();
            }
            return;
        }
        if (channel.getImportance() < NotificationManager.IMPORTANCE_NONE
                || channel.getImportance() > NotificationManager.IMPORTANCE_MAX) {
            throw new IllegalArgumentException("Invalid importance level");
        }
        // Reset fields that apps aren't allowed to set.
        if (fromTargetApp) {
            channel.setBypassDnd(r.priority == Notification.PRIORITY_MAX);
            channel.setLockscreenVisibility(r.visibility);
        }
        clearLockedFields(channel);
        if (channel.getLockscreenVisibility() == Notification.VISIBILITY_PUBLIC) {
            channel.setLockscreenVisibility(Ranking.VISIBILITY_NO_OVERRIDE);
        }
        if (!r.showBadge) {
            channel.setShowBadge(false);
        }
        r.channels.put(channel.getId(), channel);
        updateConfig();
    }

    private void clearLockedFields(NotificationChannel channel) {
        int clearMask = 0;
        for (int i = 0; i < NotificationChannel.LOCKABLE_FIELDS.length; i++) {
            clearMask |= NotificationChannel.LOCKABLE_FIELDS[i];
        }
        channel.lockFields(~clearMask);
    }

    @Override
    public void updateNotificationChannel(String pkg, int uid, NotificationChannel updatedChannel) {
        Preconditions.checkNotNull(updatedChannel);
        Preconditions.checkNotNull(updatedChannel.getId());
        Record r = getOrCreateRecord(pkg, uid);
        if (r == null) {
            throw new IllegalArgumentException("Invalid package");
        }
        NotificationChannel channel = r.channels.get(updatedChannel.getId());
        if (channel == null || channel.isDeleted()) {
            throw new IllegalArgumentException("Channel does not exist");
        }
        if (updatedChannel.getLockscreenVisibility() == Notification.VISIBILITY_PUBLIC) {
            updatedChannel.setLockscreenVisibility(Ranking.VISIBILITY_NO_OVERRIDE);
        }
        r.channels.put(updatedChannel.getId(), updatedChannel);
        updateConfig();
    }

    @Override
    public void updateNotificationChannelFromAssistant(String pkg, int uid,
            NotificationChannel updatedChannel) {
        Record r = getOrCreateRecord(pkg, uid);
        if (r == null) {
            throw new IllegalArgumentException("Invalid package");
        }
        NotificationChannel channel = r.channels.get(updatedChannel.getId());
        if (channel == null || channel.isDeleted()) {
            throw new IllegalArgumentException("Channel does not exist");
        }

        if ((channel.getUserLockedFields() & NotificationChannel.USER_LOCKED_IMPORTANCE) == 0) {
            channel.setImportance(updatedChannel.getImportance());
        }
        if ((channel.getUserLockedFields() & NotificationChannel.USER_LOCKED_LIGHTS) == 0) {
            channel.setLights(updatedChannel.shouldShowLights());
        }
        if ((channel.getUserLockedFields() & NotificationChannel.USER_LOCKED_PRIORITY) == 0) {
            channel.setBypassDnd(updatedChannel.canBypassDnd());
        }
        if ((channel.getUserLockedFields() & NotificationChannel.USER_LOCKED_SOUND) == 0) {
            channel.setSound(updatedChannel.getSound());
        }
        if ((channel.getUserLockedFields() & NotificationChannel.USER_LOCKED_VIBRATION) == 0) {
            channel.enableVibration(updatedChannel.shouldVibrate());
            channel.setVibrationPattern(updatedChannel.getVibrationPattern());
        }
        if ((channel.getUserLockedFields() & NotificationChannel.USER_LOCKED_VISIBILITY) == 0) {
            if (updatedChannel.getLockscreenVisibility() == Notification.VISIBILITY_PUBLIC) {
                channel.setLockscreenVisibility(Ranking.VISIBILITY_NO_OVERRIDE);
            } else {
                channel.setLockscreenVisibility(updatedChannel.getLockscreenVisibility());
            }
        }
        if ((channel.getUserLockedFields() & NotificationChannel.USER_LOCKED_SHOW_BADGE) == 0) {
            channel.setShowBadge(updatedChannel.canShowBadge());
        }
        if (updatedChannel.isDeleted()) {
            channel.setDeleted(true);
        }
        // Assistant cannot change the group

        r.channels.put(channel.getId(), channel);
        updateConfig();
    }

    @Override
    public NotificationChannel getNotificationChannelWithFallback(String pkg, int uid,
            String channelId, boolean includeDeleted) {
        Record r = getOrCreateRecord(pkg, uid);
        if (channelId == null) {
            channelId = NotificationChannel.DEFAULT_CHANNEL_ID;
        }
        NotificationChannel channel = r.channels.get(channelId);
        if (channel != null && (includeDeleted || !channel.isDeleted())) {
            return channel;
        } else {
            return r.channels.get(NotificationChannel.DEFAULT_CHANNEL_ID);
        }
    }

    @Override
    public NotificationChannel getNotificationChannel(String pkg, int uid, String channelId,
            boolean includeDeleted) {
        Preconditions.checkNotNull(pkg);
        Record r = getOrCreateRecord(pkg, uid);
        if (r == null) {
            return null;
        }
        if (channelId == null) {
            channelId = NotificationChannel.DEFAULT_CHANNEL_ID;
        }
        final NotificationChannel nc = r.channels.get(channelId);
        if (nc != null && (includeDeleted || !nc.isDeleted())) {
            return nc;
        }
        return null;
    }

    @Override
    public void deleteNotificationChannel(String pkg, int uid, String channelId) {
        Preconditions.checkNotNull(pkg);
        Preconditions.checkNotNull(channelId);
        Record r = getRecord(pkg, uid);
        if (r == null) {
            return;
        }
        NotificationChannel channel = r.channels.get(channelId);
        if (channel != null) {
            channel.setDeleted(true);
        }
    }

    @Override
    @VisibleForTesting
    public void permanentlyDeleteNotificationChannel(String pkg, int uid, String channelId) {
        Preconditions.checkNotNull(pkg);
        Preconditions.checkNotNull(channelId);
        Record r = getRecord(pkg, uid);
        if (r == null) {
            return;
        }
        r.channels.remove(channelId);
    }

    @Override
    public void permanentlyDeleteNotificationChannels(String pkg, int uid) {
        Preconditions.checkNotNull(pkg);
        Record r = getRecord(pkg, uid);
        if (r == null) {
            return;
        }
        int N = r.channels.size() - 1;
        for (int i = N; i >= 0; i--) {
            String key = r.channels.keyAt(i);
            if (!NotificationChannel.DEFAULT_CHANNEL_ID.equals(key)) {
                r.channels.remove(key);
            }
        }
    }

    @Override
    public ParceledListSlice<NotificationChannelGroup> getNotificationChannelGroups(String pkg,
            int uid, boolean includeDeleted) {
        Preconditions.checkNotNull(pkg);
        List<NotificationChannelGroup> groups = new ArrayList<>();
        Record r = getRecord(pkg, uid);
        if (r == null) {
            return ParceledListSlice.emptyList();
        }
        NotificationChannelGroup nonGrouped = new NotificationChannelGroup(null, null);
        int N = r.channels.size();
        for (int i = 0; i < N; i++) {
            final NotificationChannel nc = r.channels.valueAt(i);
            if (includeDeleted || !nc.isDeleted()) {
                if (nc.getGroup() != null) {
                    // lazily populate channel list
                    NotificationChannelGroup ncg = r.groups.get(nc.getGroup());
                    ncg.addChannel(nc);
                } else {
                    nonGrouped.addChannel(nc);
                }
            }
        }
        groups.addAll(r.groups.values());
        if (nonGrouped.getChannels().size() > 0) {
            groups.add(nonGrouped);
        }
        return new ParceledListSlice<>(groups);
    }

    @Override
    public ParceledListSlice<NotificationChannel> getNotificationChannels(String pkg, int uid,
            boolean includeDeleted) {
        Preconditions.checkNotNull(pkg);
        List<NotificationChannel> channels = new ArrayList<>();
        Record r = getRecord(pkg, uid);
        if (r == null) {
            return ParceledListSlice.emptyList();
        }
        int N = r.channels.size();
        for (int i = 0; i < N; i++) {
            final NotificationChannel nc = r.channels.valueAt(i);
            if (includeDeleted || !nc.isDeleted()) {
                channels.add(nc);
            }
        }
        return new ParceledListSlice<>(channels);
    }

    /**
     * Sets importance.
     */
    @Override
    public void setImportance(String pkgName, int uid, int importance) {
        getOrCreateRecord(pkgName, uid).importance = importance;
        updateConfig();
    }

    public void setEnabled(String packageName, int uid, boolean enabled) {
        boolean wasEnabled = getImportance(packageName, uid) != NotificationManager.IMPORTANCE_NONE;
        if (wasEnabled == enabled) {
            return;
        }
        setImportance(packageName, uid,
                enabled ? DEFAULT_IMPORTANCE : NotificationManager.IMPORTANCE_NONE);
    }

    public void dump(PrintWriter pw, String prefix, NotificationManagerService.DumpFilter filter) {
        if (filter == null) {
            final int N = mSignalExtractors.length;
            pw.print(prefix);
            pw.print("mSignalExtractors.length = ");
            pw.println(N);
            for (int i = 0; i < N; i++) {
                pw.print(prefix);
                pw.print("  ");
                pw.println(mSignalExtractors[i]);
            }
        }
        if (filter == null) {
            pw.print(prefix);
            pw.println("per-package config:");
        }
        pw.println("Records:");
        dumpRecords(pw, prefix, filter, mRecords);
        pw.println("Restored without uid:");
        dumpRecords(pw, prefix, filter, mRestoredWithoutUids);
    }

    private static void dumpRecords(PrintWriter pw, String prefix,
            NotificationManagerService.DumpFilter filter, ArrayMap<String, Record> records) {
        final int N = records.size();
        for (int i = 0; i < N; i++) {
            final Record r = records.valueAt(i);
            if (filter == null || filter.matches(r.pkg)) {
                pw.print(prefix);
                pw.print("  AppSettings: ");
                pw.print(r.pkg);
                pw.print(" (");
                pw.print(r.uid == Record.UNKNOWN_UID ? "UNKNOWN_UID" : Integer.toString(r.uid));
                pw.print(')');
                if (r.importance != DEFAULT_IMPORTANCE) {
                    pw.print(" importance=");
                    pw.print(Ranking.importanceToString(r.importance));
                }
                if (r.priority != DEFAULT_PRIORITY) {
                    pw.print(" priority=");
                    pw.print(Notification.priorityToString(r.priority));
                }
                if (r.visibility != DEFAULT_VISIBILITY) {
                    pw.print(" visibility=");
                    pw.print(Notification.visibilityToString(r.visibility));
                }
                pw.print(" showBadge=");
                pw.print(Boolean.toString(r.showBadge));
                pw.println();
                for (NotificationChannel channel : r.channels.values()) {
                    pw.print(prefix);
                    pw.print("  ");
                    pw.print("  ");
                    pw.println(channel);
                }
                for (NotificationChannelGroup group : r.groups.values()) {
                    pw.print(prefix);
                    pw.print("  ");
                    pw.print("  ");
                    pw.println(group);
                }
            }
        }
    }

    public JSONObject dumpJson(NotificationManagerService.DumpFilter filter) {
        JSONObject ranking = new JSONObject();
        JSONArray records = new JSONArray();
        try {
            ranking.put("noUid", mRestoredWithoutUids.size());
        } catch (JSONException e) {
           // pass
        }
        final int N = mRecords.size();
        for (int i = 0; i < N; i++) {
            final Record r = mRecords.valueAt(i);
            if (filter == null || filter.matches(r.pkg)) {
                JSONObject record = new JSONObject();
                try {
                    record.put("userId", UserHandle.getUserId(r.uid));
                    record.put("packageName", r.pkg);
                    if (r.importance != DEFAULT_IMPORTANCE) {
                        record.put("importance", Ranking.importanceToString(r.importance));
                    }
                    if (r.priority != DEFAULT_PRIORITY) {
                        record.put("priority", Notification.priorityToString(r.priority));
                    }
                    if (r.visibility != DEFAULT_VISIBILITY) {
                        record.put("visibility", Notification.visibilityToString(r.visibility));
                    }
                    if (r.showBadge != DEFAULT_SHOW_BADGE) {
                        record.put("showBadge", Boolean.valueOf(r.showBadge));
                    }
                    for (NotificationChannel channel : r.channels.values()) {
                        record.put("channel", channel.toJson());
                    }
                    for (NotificationChannelGroup group : r.groups.values()) {
                        record.put("group", group.toJson());
                    }
                } catch (JSONException e) {
                   // pass
                }
                records.put(record);
            }
        }
        try {
            ranking.put("records", records);
        } catch (JSONException e) {
            // pass
        }
        return ranking;
    }

    /**
     * Dump only the ban information as structured JSON for the stats collector.
     *
     * This is intentionally redundant with {#link dumpJson} because the old
     * scraper will expect this format.
     *
     * @param filter
     * @return
     */
    public JSONArray dumpBansJson(NotificationManagerService.DumpFilter filter) {
        JSONArray bans = new JSONArray();
        Map<Integer, String> packageBans = getPackageBans();
        for(Entry<Integer, String> ban : packageBans.entrySet()) {
            final int userId = UserHandle.getUserId(ban.getKey());
            final String packageName = ban.getValue();
            if (filter == null || filter.matches(packageName)) {
                JSONObject banJson = new JSONObject();
                try {
                    banJson.put("userId", userId);
                    banJson.put("packageName", packageName);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
                bans.put(banJson);
            }
        }
        return bans;
    }

    public Map<Integer, String> getPackageBans() {
        final int N = mRecords.size();
        ArrayMap<Integer, String> packageBans = new ArrayMap<>(N);
        for (int i = 0; i < N; i++) {
            final Record r = mRecords.valueAt(i);
            if (r.importance == NotificationManager.IMPORTANCE_NONE) {
                packageBans.put(r.uid, r.pkg);
            }
        }
        return packageBans;
    }

    public void onPackagesChanged(boolean removingPackage, int changeUserId, String[] pkgList,
            int[] uidList) {
        if (pkgList == null || pkgList.length == 0) {
            return; // nothing to do
        }
        boolean updated = false;
        if (removingPackage) {
            // Remove notification settings for uninstalled package
            int size = Math.min(pkgList.length, uidList.length);
            for (int i = 0; i < size; i++) {
                final String pkg = pkgList[i];
                final int uid = uidList[i];
                mRecords.remove(recordKey(pkg, uid));
                mRestoredWithoutUids.remove(pkg);
                updated = true;
            }
        } else {
            for (String pkg : pkgList) {
                // Package install
                final Record r = mRestoredWithoutUids.get(pkg);
                if (r != null) {
                    try {
                        r.uid = mPm.getPackageUidAsUser(r.pkg, changeUserId);
                        mRestoredWithoutUids.remove(pkg);
                        mRecords.put(recordKey(r.pkg, r.uid), r);
                        updated = true;
                    } catch (NameNotFoundException e) {
                        // noop
                    }
                }
                // Package upgrade
                try {
                    Record fullRecord = getRecord(pkg,
                            mPm.getPackageUidAsUser(pkg, changeUserId));
                    if (fullRecord != null) {
                        clampDefaultChannel(fullRecord);
                    }
                } catch (NameNotFoundException e) {
                }
            }
        }

        if (updated) {
            updateConfig();
        }
    }

    private static class Record {
        static int UNKNOWN_UID = UserHandle.USER_NULL;

        String pkg;
        int uid = UNKNOWN_UID;
        int importance = DEFAULT_IMPORTANCE;
        int priority = DEFAULT_PRIORITY;
        int visibility = DEFAULT_VISIBILITY;
        boolean showBadge = DEFAULT_SHOW_BADGE;

        ArrayMap<String, NotificationChannel> channels = new ArrayMap<>();
        ArrayMap<String, NotificationChannelGroup> groups = new ArrayMap<>();
   }
}