services/core/java/com/android/server/om/OverlayManagerSettings.java - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2016 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.om;

 import static android.content.om.OverlayInfo.STATE_UNKNOWN;

 import static com.android.server.om.OverlayManagerService.DEBUG;
 import static com.android.server.om.OverlayManagerService.TAG;

 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.content.om.OverlayInfo;
 import android.util.AndroidRuntimeException;
 import android.util.ArrayMap;
 import android.util.Slog;
 import android.util.Xml;

 import com.android.internal.util.FastXmlSerializer;
 import com.android.internal.util.XmlUtils;

 import org.xmlpull.v1.XmlPullParser;
 import org.xmlpull.v1.XmlPullParserException;

 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.io.PrintWriter;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.ListIterator;
 import java.util.Map;

 /**
  * Data structure representing the current state of all overlay packages in the
  * system.
  *
  * Modifications to the data are exposed through the ChangeListener interface.
  *
  * @see ChangeListener
  * @see OverlayManagerService
  */
 final class OverlayManagerSettings {
     private final List<ChangeListener> mListeners = new ArrayList<>();

     private final ArrayList<SettingsItem> mItems = new ArrayList<>();

     void init(@NonNull final String packageName, final int userId,
             @NonNull final String targetPackageName, @NonNull final String baseCodePath) {
         remove(packageName, userId);
         final SettingsItem item =
                 new SettingsItem(packageName, userId, targetPackageName, baseCodePath);
         mItems.add(item);
     }

     void remove(@NonNull final String packageName, final int userId) {
         final SettingsItem item = select(packageName, userId);
         if (item == null) {
             return;
         }
         final OverlayInfo oi = item.getOverlayInfo();
         mItems.remove(item);
         if (oi != null) {
             notifyOverlayRemoved(oi);
         }
     }

     boolean contains(@NonNull final String packageName, final int userId) {
         return select(packageName, userId) != null;
     }

     OverlayInfo getOverlayInfo(@NonNull final String packageName, final int userId)
             throws BadKeyException {
         final SettingsItem item = select(packageName, userId);
         if (item == null) {
             throw new BadKeyException(packageName, userId);
         }
         return item.getOverlayInfo();
     }

     String getTargetPackageName(@NonNull final String packageName, final int userId)
             throws BadKeyException {
         final SettingsItem item = select(packageName, userId);
         if (item == null) {
             throw new BadKeyException(packageName, userId);
         }
         return item.getTargetPackageName();
     }

     void setBaseCodePath(@NonNull final String packageName, final int userId,
             @NonNull final String path) throws BadKeyException {
         final SettingsItem item = select(packageName, userId);
         if (item == null) {
             throw new BadKeyException(packageName, userId);
         }
         item.setBaseCodePath(path);
         notifySettingsChanged();
     }

     boolean getEnabled(@NonNull final String packageName, final int userId) throws BadKeyException {
         final SettingsItem item = select(packageName, userId);
         if (item == null) {
             throw new BadKeyException(packageName, userId);
         }
         return item.isEnabled();
     }

     void setEnabled(@NonNull final String packageName, final int userId, final boolean enable)
             throws BadKeyException {
         final SettingsItem item = select(packageName, userId);
         if (item == null) {
             throw new BadKeyException(packageName, userId);
         }
         if (enable == item.isEnabled()) {
             return; // nothing to do
         }

         item.setEnabled(enable);
         notifySettingsChanged();
     }

     int getState(@NonNull final String packageName, final int userId) throws BadKeyException {
         final SettingsItem item = select(packageName, userId);
         if (item == null) {
             throw new BadKeyException(packageName, userId);
         }
         return item.getState();
     }

     void setState(@NonNull final String packageName, final int userId, final int state)
             throws BadKeyException {
         final SettingsItem item = select(packageName, userId);
         if (item == null) {
             throw new BadKeyException(packageName, userId);
         }
         final OverlayInfo previous = item.getOverlayInfo();
         item.setState(state);
         final OverlayInfo current = item.getOverlayInfo();
         if (previous.state == STATE_UNKNOWN) {
             notifyOverlayAdded(current);
             notifySettingsChanged();
         } else if (current.state != previous.state) {
             notifyOverlayChanged(current, previous);
             notifySettingsChanged();
         }
     }

     List<OverlayInfo> getOverlaysForTarget(@NonNull final String targetPackageName,
             final int userId) {
         final List<SettingsItem> items = selectWhereTarget(targetPackageName, userId);
         if (items.isEmpty()) {
             return Collections.emptyList();
         }
         final List<OverlayInfo> out = new ArrayList<>(items.size());
         final int N = items.size();
         for (int i = 0; i < N; i++) {
             final SettingsItem item = items.get(i);
             out.add(item.getOverlayInfo());
         }
         return out;
     }

     ArrayMap<String, List<OverlayInfo>> getOverlaysForUser(final int userId) {
         final List<SettingsItem> items = selectWhereUser(userId);
         if (items.isEmpty()) {
             return ArrayMap.EMPTY;
         }
         final ArrayMap<String, List<OverlayInfo>> out = new ArrayMap<>(items.size());
         final int N = items.size();
         for (int i = 0; i < N; i++) {
             final SettingsItem item = items.get(i);
             final String targetPackageName = item.getTargetPackageName();
             if (!out.containsKey(targetPackageName)) {
                 out.put(targetPackageName, new ArrayList<OverlayInfo>());
             }
             final List<OverlayInfo> overlays = out.get(targetPackageName);
             overlays.add(item.getOverlayInfo());
         }
         return out;
     }

     List<String> getTargetPackageNamesForUser(final int userId) {
         final List<SettingsItem> items = selectWhereUser(userId);
         if (items.isEmpty()) {
             return Collections.emptyList();
         }
         final List<String> out = new ArrayList<>();
         final int N = items.size();
         for (int i = 0; i < N; i++) {
             final SettingsItem item = items.get(i);
             final String targetPackageName = item.getTargetPackageName();
             if (!out.contains(targetPackageName)) {
                 out.add(targetPackageName);
             }
         }
         return out;
     }

     List<Integer> getUsers() {
         final ArrayList<Integer> users = new ArrayList<>();
         final int N = mItems.size();
         for (int i = 0; i < N; i++) {
             final SettingsItem item = mItems.get(i);
             if (!users.contains(item.userId)) {
                 users.add(item.userId);
             }
         }
         return users;
     }

     void removeUser(final int userId) {
         final Iterator<SettingsItem> iter = mItems.iterator();
         while (iter.hasNext()) {
             final SettingsItem item = iter.next();
             if (item.userId == userId) {
                 iter.remove();
             }
         }
     }

     boolean setPriority(@NonNull final String packageName,
             @NonNull final String newParentPackageName, final int userId) {
         if (packageName.equals(newParentPackageName)) {
             return false;
         }
         final SettingsItem rowToMove = select(packageName, userId);
         if (rowToMove == null) {
             return false;
         }
         final SettingsItem newParentRow = select(newParentPackageName, userId);
         if (newParentRow == null) {
             return false;
         }
         if (!rowToMove.getTargetPackageName().equals(newParentRow.getTargetPackageName())) {
             return false;
         }

         mItems.remove(rowToMove);
         final ListIterator<SettingsItem> iter = mItems.listIterator();
         while (iter.hasNext()) {
             final SettingsItem item = iter.next();
             if (item.userId == userId && item.packageName.equals(newParentPackageName)) {
                 iter.add(rowToMove);
                 notifyOverlayPriorityChanged(rowToMove.getOverlayInfo());
                 notifySettingsChanged();
                 return true;
             }
         }

         Slog.wtf(TAG, "failed to find the parent item a second time");
         return false;
     }

     boolean setLowestPriority(@NonNull final String packageName, final int userId) {
         final SettingsItem item = select(packageName, userId);
         if (item == null) {
             return false;
         }
         mItems.remove(item);
         mItems.add(0, item);
         notifyOverlayPriorityChanged(item.getOverlayInfo());
         notifySettingsChanged();
         return true;
     }

     boolean setHighestPriority(@NonNull final String packageName, final int userId) {
         final SettingsItem item = select(packageName, userId);
         if (item == null) {
             return false;
         }
         mItems.remove(item);
         mItems.add(item);
         notifyOverlayPriorityChanged(item.getOverlayInfo());
         notifySettingsChanged();
         return true;
     }

     private static final String TAB1 = "    ";
     private static final String TAB2 = TAB1 + TAB1;
     private static final String TAB3 = TAB2 + TAB1;

     void dump(@NonNull final PrintWriter pw) {
         pw.println("Settings");
         dumpItems(pw);
         dumpListeners(pw);
     }

     private void dumpItems(@NonNull final PrintWriter pw) {
         pw.println(TAB1 + "Items");

         if (mItems.isEmpty()) {
             pw.println(TAB2 + "<none>");
             return;
         }

         final int N = mItems.size();
         for (int i = 0; i < N; i++) {
             final SettingsItem item = mItems.get(i);
             final StringBuilder sb = new StringBuilder();
             sb.append(TAB2 + item.packageName + ":" + item.userId + " {\n");
             sb.append(TAB3 + "packageName.......: " + item.packageName + "\n");
             sb.append(TAB3 + "userId............: " + item.userId + "\n");
             sb.append(TAB3 + "targetPackageName.: " + item.getTargetPackageName() + "\n");
             sb.append(TAB3 + "baseCodePath......: " + item.getBaseCodePath() + "\n");
             sb.append(TAB3 + "state.............: " + OverlayInfo.stateToString(item.getState()) + "\n");
             sb.append(TAB3 + "isEnabled.........: " + item.isEnabled() + "\n");
             sb.append(TAB2 + "}");
             pw.println(sb.toString());
         }
     }

     private void dumpListeners(@NonNull final PrintWriter pw) {
         pw.println(TAB1 + "Change listeners");

         if (mListeners.isEmpty()) {
             pw.println(TAB2 + "<none>");
             return;
         }

         final int N = mListeners.size();
         for (int i = 0; i < N; i++) {
             final ChangeListener ch = mListeners.get(i);
             pw.println(TAB2 + ch);
         }

     }

     void restore(@NonNull final InputStream is) throws IOException, XmlPullParserException {
         Serializer.restore(mItems, is);
     }

     void persist(@NonNull final OutputStream os) throws IOException, XmlPullParserException {
         Serializer.persist(mItems, os);
     }

     private static final class Serializer {
         private static final String TAG_OVERLAYS = "overlays";
         private static final String TAG_ITEM = "item";

         private static final String ATTR_BASE_CODE_PATH = "baseCodePath";
         private static final String ATTR_IS_ENABLED = "isEnabled";
         private static final String ATTR_PACKAGE_NAME = "packageName";
         private static final String ATTR_STATE = "state";
         private static final String ATTR_TARGET_PACKAGE_NAME = "targetPackageName";
         private static final String ATTR_USER_ID = "userId";
         private static final String ATTR_VERSION = "version";

         private static final int CURRENT_VERSION = 1;

         public static void restore(@NonNull final ArrayList<SettingsItem> table,
                 @NonNull final InputStream is) throws IOException, XmlPullParserException {

             try (InputStreamReader reader = new InputStreamReader(is)) {
                 table.clear();
                 final XmlPullParser parser = Xml.newPullParser();
                 parser.setInput(reader);
                 XmlUtils.beginDocument(parser, TAG_OVERLAYS);
                 int version = XmlUtils.readIntAttribute(parser, ATTR_VERSION);
                 if (version != CURRENT_VERSION) {
                     throw new XmlPullParserException("unrecognized version " + version);
                 }
                 int depth = parser.getDepth();

                 while (XmlUtils.nextElementWithin(parser, depth)) {
                     switch (parser.getName()) {
                         case TAG_ITEM:
                             final SettingsItem item = restoreRow(parser, depth + 1);
                             table.add(item);
                             break;
                     }
                 }
             }
         }

         private static SettingsItem restoreRow(@NonNull final XmlPullParser parser, final int depth)
                 throws IOException {
             final String packageName = XmlUtils.readStringAttribute(parser, ATTR_PACKAGE_NAME);
             final int userId = XmlUtils.readIntAttribute(parser, ATTR_USER_ID);
             final String targetPackageName = XmlUtils.readStringAttribute(parser,
                     ATTR_TARGET_PACKAGE_NAME);
             final String baseCodePath = XmlUtils.readStringAttribute(parser, ATTR_BASE_CODE_PATH);
             final int state = XmlUtils.readIntAttribute(parser, ATTR_STATE);
             final boolean isEnabled = XmlUtils.readBooleanAttribute(parser, ATTR_IS_ENABLED);

             return new SettingsItem(packageName, userId, targetPackageName, baseCodePath, state,
                     isEnabled);
         }

         public static void persist(@NonNull final ArrayList<SettingsItem> table,
                 @NonNull final OutputStream os) throws IOException, XmlPullParserException {
             final FastXmlSerializer xml = new FastXmlSerializer();
             xml.setOutput(os, "utf-8");
             xml.startDocument(null, true);
             xml.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
             xml.startTag(null, TAG_OVERLAYS);
             XmlUtils.writeIntAttribute(xml, ATTR_VERSION, CURRENT_VERSION);

             final int N = table.size();
             for (int i = 0; i < N; i++) {
                 final SettingsItem item = table.get(i);
                 persistRow(xml, item);
             }
             xml.endTag(null, TAG_OVERLAYS);
             xml.endDocument();
         }

         private static void persistRow(@NonNull final FastXmlSerializer xml,
                 @NonNull final SettingsItem item) throws IOException {
             xml.startTag(null, TAG_ITEM);
             XmlUtils.writeStringAttribute(xml, ATTR_PACKAGE_NAME, item.packageName);
             XmlUtils.writeIntAttribute(xml, ATTR_USER_ID, item.userId);
             XmlUtils.writeStringAttribute(xml, ATTR_TARGET_PACKAGE_NAME, item.targetPackageName);
             XmlUtils.writeStringAttribute(xml, ATTR_BASE_CODE_PATH, item.baseCodePath);
             XmlUtils.writeIntAttribute(xml, ATTR_STATE, item.state);
             XmlUtils.writeBooleanAttribute(xml, ATTR_IS_ENABLED, item.isEnabled);
             xml.endTag(null, TAG_ITEM);
         }
     }

     private static final class SettingsItem {
         private final int userId;
         private final String packageName;
         private final String targetPackageName;
         private String baseCodePath;
         private int state;
         private boolean isEnabled;
         private OverlayInfo cache;

         SettingsItem(@NonNull final String packageName, final int userId,
                 @NonNull final String targetPackageName, @NonNull final String baseCodePath,
                 final int state, final boolean isEnabled) {
             this.packageName = packageName;
             this.userId = userId;
             this.targetPackageName = targetPackageName;
             this.baseCodePath = baseCodePath;
             this.state = state;
             this.isEnabled = isEnabled;
             cache = null;
         }

         SettingsItem(@NonNull final String packageName, final int userId,
                 @NonNull final String targetPackageName, @NonNull final String baseCodePath) {
             this(packageName, userId, targetPackageName, baseCodePath, STATE_UNKNOWN,
                     false);
         }

         private String getTargetPackageName() {
             return targetPackageName;
         }

         private String getBaseCodePath() {
             return baseCodePath;
         }

         private void setBaseCodePath(@NonNull final String path) {
             if (!baseCodePath.equals(path)) {
                 baseCodePath = path;
                 invalidateCache();
             }
         }

         private int getState() {
             return state;
         }

         private void setState(final int state) {
             if (this.state != state) {
                 this.state = state;
                 invalidateCache();
             }
         }

         private boolean isEnabled() {
             return isEnabled;
         }

         private void setEnabled(final boolean enable) {
             if (isEnabled != enable) {
                 isEnabled = enable;
                 invalidateCache();
             }
         }

         private OverlayInfo getOverlayInfo() {
             if (cache == null) {
                 cache = new OverlayInfo(packageName, targetPackageName, baseCodePath,
                         state, userId);
             }
             return cache;
         }

         private void invalidateCache() {
             cache = null;
         }
     }

     private SettingsItem select(@NonNull final String packageName, final int userId) {
         final int N = mItems.size();
         for (int i = 0; i < N; i++) {
             final SettingsItem item = mItems.get(i);
             if (item.userId == userId && item.packageName.equals(packageName)) {
                 return item;
             }
         }
         return null;
     }

     private List<SettingsItem> selectWhereUser(final int userId) {
         final ArrayList<SettingsItem> items = new ArrayList<>();
         final int N = mItems.size();
         for (int i = 0; i < N; i++) {
             final SettingsItem item = mItems.get(i);
             if (item.userId == userId) {
                 items.add(item);
             }
         }
         return items;
     }

     private List<SettingsItem> selectWhereTarget(@NonNull final String targetPackageName,
             final int userId) {
         final ArrayList<SettingsItem> items = new ArrayList<>();
         final int N = mItems.size();
         for (int i = 0; i < N; i++) {
             final SettingsItem item = mItems.get(i);
             if (item.userId == userId && item.getTargetPackageName().equals(targetPackageName)) {
                 items.add(item);
             }
         }
         return items;
     }

     private void assertNotNull(@Nullable final Object o) {
         if (o == null) {
             throw new AndroidRuntimeException("object must not be null");
         }
     }

     void addChangeListener(@NonNull final ChangeListener listener) {
         mListeners.add(listener);
     }

     void removeChangeListener(@NonNull final ChangeListener listener) {
         mListeners.remove(listener);
     }

     private void notifySettingsChanged() {
         final int N = mListeners.size();
         for (int i = 0; i < N; i++) {
             final ChangeListener listener = mListeners.get(i);
             listener.onSettingsChanged();
         }
     }

     private void notifyOverlayAdded(@NonNull final OverlayInfo oi) {
         if (DEBUG) {
             assertNotNull(oi);
         }
         final int N = mListeners.size();
         for (int i = 0; i < N; i++) {
             final ChangeListener listener = mListeners.get(i);
             listener.onOverlayAdded(oi);
         }
     }

     private void notifyOverlayRemoved(@NonNull final OverlayInfo oi) {
         if (DEBUG) {
             assertNotNull(oi);
         }
         final int N = mListeners.size();
         for (int i = 0; i < N; i++) {
             final ChangeListener listener = mListeners.get(i);
             listener.onOverlayRemoved(oi);
         }
     }

     private void notifyOverlayChanged(@NonNull final OverlayInfo oi,
             @NonNull final OverlayInfo oldOi) {
         if (DEBUG) {
             assertNotNull(oi);
             assertNotNull(oldOi);
         }
         final int N = mListeners.size();
         for (int i = 0; i < N; i++) {
             final ChangeListener listener = mListeners.get(i);
             listener.onOverlayChanged(oi, oldOi);
         }
     }

     private void notifyOverlayPriorityChanged(@NonNull final OverlayInfo oi) {
         if (DEBUG) {
             assertNotNull(oi);
         }
         final int N = mListeners.size();
         for (int i = 0; i < N; i++) {
             final ChangeListener listener = mListeners.get(i);
             listener.onOverlayPriorityChanged(oi);
         }
     }

     interface ChangeListener {
         void onSettingsChanged();
         void onOverlayAdded(@NonNull OverlayInfo oi);
         void onOverlayRemoved(@NonNull OverlayInfo oi);
         void onOverlayChanged(@NonNull OverlayInfo oi, @NonNull OverlayInfo oldOi);
         void onOverlayPriorityChanged(@NonNull OverlayInfo oi);
     }

     static final class BadKeyException extends RuntimeException {
         BadKeyException(@NonNull final String packageName, final int userId) {
             super("Bad key packageName=" + packageName + " userId=" + userId);
         }
     }
 }
	/*
	* Copyright (C) 2016 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.om;

	import static android.content.om.OverlayInfo.STATE_UNKNOWN;

	import static com.android.server.om.OverlayManagerService.DEBUG;
	import static com.android.server.om.OverlayManagerService.TAG;

	import android.annotation.NonNull;
	import android.annotation.Nullable;
	import android.content.om.OverlayInfo;
	import android.util.AndroidRuntimeException;
	import android.util.ArrayMap;
	import android.util.Slog;
	import android.util.Xml;

	import com.android.internal.util.FastXmlSerializer;
	import com.android.internal.util.XmlUtils;

	import org.xmlpull.v1.XmlPullParser;
	import org.xmlpull.v1.XmlPullParserException;

	import java.io.IOException;
	import java.io.InputStream;
	import java.io.InputStreamReader;
	import java.io.OutputStream;
	import java.io.PrintWriter;
	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.Iterator;
	import java.util.List;
	import java.util.ListIterator;
	import java.util.Map;

	/**
	* Data structure representing the current state of all overlay packages in the
	* system.
	*
	* Modifications to the data are exposed through the ChangeListener interface.
	*
	* @see ChangeListener
	* @see OverlayManagerService
	*/
	final class OverlayManagerSettings {
	private final List<ChangeListener> mListeners = new ArrayList<>();

	private final ArrayList<SettingsItem> mItems = new ArrayList<>();

	void init(@NonNull final String packageName, final int userId,
	@NonNull final String targetPackageName, @NonNull final String baseCodePath) {
	remove(packageName, userId);
	final SettingsItem item =
	new SettingsItem(packageName, userId, targetPackageName, baseCodePath);
	mItems.add(item);
	}

	void remove(@NonNull final String packageName, final int userId) {
	final SettingsItem item = select(packageName, userId);
	if (item == null) {
	return;
	}
	final OverlayInfo oi = item.getOverlayInfo();
	mItems.remove(item);
	if (oi != null) {
	notifyOverlayRemoved(oi);
	}
	}

	boolean contains(@NonNull final String packageName, final int userId) {
	return select(packageName, userId) != null;
	}

	OverlayInfo getOverlayInfo(@NonNull final String packageName, final int userId)
	throws BadKeyException {
	final SettingsItem item = select(packageName, userId);
	if (item == null) {
	throw new BadKeyException(packageName, userId);
	}
	return item.getOverlayInfo();
	}

	String getTargetPackageName(@NonNull final String packageName, final int userId)
	throws BadKeyException {
	final SettingsItem item = select(packageName, userId);
	if (item == null) {
	throw new BadKeyException(packageName, userId);
	}
	return item.getTargetPackageName();
	}

	void setBaseCodePath(@NonNull final String packageName, final int userId,
	@NonNull final String path) throws BadKeyException {
	final SettingsItem item = select(packageName, userId);
	if (item == null) {
	throw new BadKeyException(packageName, userId);
	}
	item.setBaseCodePath(path);
	notifySettingsChanged();
	}

	boolean getEnabled(@NonNull final String packageName, final int userId) throws BadKeyException {
	final SettingsItem item = select(packageName, userId);
	if (item == null) {
	throw new BadKeyException(packageName, userId);
	}
	return item.isEnabled();
	}

	void setEnabled(@NonNull final String packageName, final int userId, final boolean enable)
	throws BadKeyException {
	final SettingsItem item = select(packageName, userId);
	if (item == null) {
	throw new BadKeyException(packageName, userId);
	}
	if (enable == item.isEnabled()) {
	return; // nothing to do
	}

	item.setEnabled(enable);
	notifySettingsChanged();
	}

	int getState(@NonNull final String packageName, final int userId) throws BadKeyException {
	final SettingsItem item = select(packageName, userId);
	if (item == null) {
	throw new BadKeyException(packageName, userId);
	}
	return item.getState();
	}

	void setState(@NonNull final String packageName, final int userId, final int state)
	throws BadKeyException {
	final SettingsItem item = select(packageName, userId);
	if (item == null) {
	throw new BadKeyException(packageName, userId);
	}
	final OverlayInfo previous = item.getOverlayInfo();
	item.setState(state);
	final OverlayInfo current = item.getOverlayInfo();
	if (previous.state == STATE_UNKNOWN) {
	notifyOverlayAdded(current);
	notifySettingsChanged();
	} else if (current.state != previous.state) {
	notifyOverlayChanged(current, previous);
	notifySettingsChanged();
	}
	}

	List<OverlayInfo> getOverlaysForTarget(@NonNull final String targetPackageName,
	final int userId) {
	final List<SettingsItem> items = selectWhereTarget(targetPackageName, userId);
	if (items.isEmpty()) {
	return Collections.emptyList();
	}
	final List<OverlayInfo> out = new ArrayList<>(items.size());
	final int N = items.size();
	for (int i = 0; i < N; i++) {
	final SettingsItem item = items.get(i);
	out.add(item.getOverlayInfo());
	}
	return out;
	}

	ArrayMap<String, List<OverlayInfo>> getOverlaysForUser(final int userId) {
	final List<SettingsItem> items = selectWhereUser(userId);
	if (items.isEmpty()) {
	return ArrayMap.EMPTY;
	}
	final ArrayMap<String, List<OverlayInfo>> out = new ArrayMap<>(items.size());
	final int N = items.size();
	for (int i = 0; i < N; i++) {
	final SettingsItem item = items.get(i);
	final String targetPackageName = item.getTargetPackageName();
	if (!out.containsKey(targetPackageName)) {
	out.put(targetPackageName, new ArrayList<OverlayInfo>());
	}
	final List<OverlayInfo> overlays = out.get(targetPackageName);
	overlays.add(item.getOverlayInfo());
	}
	return out;
	}

	List<String> getTargetPackageNamesForUser(final int userId) {
	final List<SettingsItem> items = selectWhereUser(userId);
	if (items.isEmpty()) {
	return Collections.emptyList();
	}
	final List<String> out = new ArrayList<>();
	final int N = items.size();
	for (int i = 0; i < N; i++) {
	final SettingsItem item = items.get(i);
	final String targetPackageName = item.getTargetPackageName();
	if (!out.contains(targetPackageName)) {
	out.add(targetPackageName);
	}
	}
	return out;
	}

	List<Integer> getUsers() {
	final ArrayList<Integer> users = new ArrayList<>();
	final int N = mItems.size();
	for (int i = 0; i < N; i++) {
	final SettingsItem item = mItems.get(i);
	if (!users.contains(item.userId)) {
	users.add(item.userId);
	}
	}
	return users;
	}

	void removeUser(final int userId) {
	final Iterator<SettingsItem> iter = mItems.iterator();
	while (iter.hasNext()) {
	final SettingsItem item = iter.next();
	if (item.userId == userId) {
	iter.remove();
	}
	}
	}

	boolean setPriority(@NonNull final String packageName,
	@NonNull final String newParentPackageName, final int userId) {
	if (packageName.equals(newParentPackageName)) {
	return false;
	}
	final SettingsItem rowToMove = select(packageName, userId);
	if (rowToMove == null) {
	return false;
	}
	final SettingsItem newParentRow = select(newParentPackageName, userId);
	if (newParentRow == null) {
	return false;
	}
	if (!rowToMove.getTargetPackageName().equals(newParentRow.getTargetPackageName())) {
	return false;
	}

	mItems.remove(rowToMove);
	final ListIterator<SettingsItem> iter = mItems.listIterator();
	while (iter.hasNext()) {
	final SettingsItem item = iter.next();
	if (item.userId == userId && item.packageName.equals(newParentPackageName)) {
	iter.add(rowToMove);
	notifyOverlayPriorityChanged(rowToMove.getOverlayInfo());
	notifySettingsChanged();
	return true;
	}
	}

	Slog.wtf(TAG, "failed to find the parent item a second time");
	return false;
	}

	boolean setLowestPriority(@NonNull final String packageName, final int userId) {
	final SettingsItem item = select(packageName, userId);
	if (item == null) {
	return false;
	}
	mItems.remove(item);
	mItems.add(0, item);
	notifyOverlayPriorityChanged(item.getOverlayInfo());
	notifySettingsChanged();
	return true;
	}

	boolean setHighestPriority(@NonNull final String packageName, final int userId) {
	final SettingsItem item = select(packageName, userId);
	if (item == null) {
	return false;
	}
	mItems.remove(item);
	mItems.add(item);
	notifyOverlayPriorityChanged(item.getOverlayInfo());
	notifySettingsChanged();
	return true;
	}

	private static final String TAB1 = " ";
	private static final String TAB2 = TAB1 + TAB1;
	private static final String TAB3 = TAB2 + TAB1;

	void dump(@NonNull final PrintWriter pw) {
	pw.println("Settings");
	dumpItems(pw);
	dumpListeners(pw);
	}

	private void dumpItems(@NonNull final PrintWriter pw) {
	pw.println(TAB1 + "Items");

	if (mItems.isEmpty()) {
	pw.println(TAB2 + "<none>");
	return;
	}

	final int N = mItems.size();
	for (int i = 0; i < N; i++) {
	final SettingsItem item = mItems.get(i);
	final StringBuilder sb = new StringBuilder();
	sb.append(TAB2 + item.packageName + ":" + item.userId + " {\n");
	sb.append(TAB3 + "packageName.......: " + item.packageName + "\n");
	sb.append(TAB3 + "userId............: " + item.userId + "\n");
	sb.append(TAB3 + "targetPackageName.: " + item.getTargetPackageName() + "\n");
	sb.append(TAB3 + "baseCodePath......: " + item.getBaseCodePath() + "\n");
	sb.append(TAB3 + "state.............: " + OverlayInfo.stateToString(item.getState()) + "\n");
	sb.append(TAB3 + "isEnabled.........: " + item.isEnabled() + "\n");
	sb.append(TAB2 + "}");
	pw.println(sb.toString());
	}
	}

	private void dumpListeners(@NonNull final PrintWriter pw) {
	pw.println(TAB1 + "Change listeners");

	if (mListeners.isEmpty()) {
	pw.println(TAB2 + "<none>");
	return;
	}

	final int N = mListeners.size();
	for (int i = 0; i < N; i++) {
	final ChangeListener ch = mListeners.get(i);
	pw.println(TAB2 + ch);
	}

	}

	void restore(@NonNull final InputStream is) throws IOException, XmlPullParserException {
	Serializer.restore(mItems, is);
	}

	void persist(@NonNull final OutputStream os) throws IOException, XmlPullParserException {
	Serializer.persist(mItems, os);
	}

	private static final class Serializer {
	private static final String TAG_OVERLAYS = "overlays";
	private static final String TAG_ITEM = "item";

	private static final String ATTR_BASE_CODE_PATH = "baseCodePath";
	private static final String ATTR_IS_ENABLED = "isEnabled";
	private static final String ATTR_PACKAGE_NAME = "packageName";
	private static final String ATTR_STATE = "state";
	private static final String ATTR_TARGET_PACKAGE_NAME = "targetPackageName";
	private static final String ATTR_USER_ID = "userId";
	private static final String ATTR_VERSION = "version";

	private static final int CURRENT_VERSION = 1;

	public static void restore(@NonNull final ArrayList<SettingsItem> table,
	@NonNull final InputStream is) throws IOException, XmlPullParserException {

	try (InputStreamReader reader = new InputStreamReader(is)) {
	table.clear();
	final XmlPullParser parser = Xml.newPullParser();
	parser.setInput(reader);
	XmlUtils.beginDocument(parser, TAG_OVERLAYS);
	int version = XmlUtils.readIntAttribute(parser, ATTR_VERSION);
	if (version != CURRENT_VERSION) {
	throw new XmlPullParserException("unrecognized version " + version);
	}
	int depth = parser.getDepth();

	while (XmlUtils.nextElementWithin(parser, depth)) {
	switch (parser.getName()) {
	case TAG_ITEM:
	final SettingsItem item = restoreRow(parser, depth + 1);
	table.add(item);
	break;
	}
	}
	}
	}

	private static SettingsItem restoreRow(@NonNull final XmlPullParser parser, final int depth)
	throws IOException {
	final String packageName = XmlUtils.readStringAttribute(parser, ATTR_PACKAGE_NAME);
	final int userId = XmlUtils.readIntAttribute(parser, ATTR_USER_ID);
	final String targetPackageName = XmlUtils.readStringAttribute(parser,
	ATTR_TARGET_PACKAGE_NAME);
	final String baseCodePath = XmlUtils.readStringAttribute(parser, ATTR_BASE_CODE_PATH);
	final int state = XmlUtils.readIntAttribute(parser, ATTR_STATE);
	final boolean isEnabled = XmlUtils.readBooleanAttribute(parser, ATTR_IS_ENABLED);

	return new SettingsItem(packageName, userId, targetPackageName, baseCodePath, state,
	isEnabled);
	}

	public static void persist(@NonNull final ArrayList<SettingsItem> table,
	@NonNull final OutputStream os) throws IOException, XmlPullParserException {
	final FastXmlSerializer xml = new FastXmlSerializer();
	xml.setOutput(os, "utf-8");
	xml.startDocument(null, true);
	xml.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
	xml.startTag(null, TAG_OVERLAYS);
	XmlUtils.writeIntAttribute(xml, ATTR_VERSION, CURRENT_VERSION);

	final int N = table.size();
	for (int i = 0; i < N; i++) {
	final SettingsItem item = table.get(i);
	persistRow(xml, item);
	}
	xml.endTag(null, TAG_OVERLAYS);
	xml.endDocument();
	}

	private static void persistRow(@NonNull final FastXmlSerializer xml,
	@NonNull final SettingsItem item) throws IOException {
	xml.startTag(null, TAG_ITEM);
	XmlUtils.writeStringAttribute(xml, ATTR_PACKAGE_NAME, item.packageName);
	XmlUtils.writeIntAttribute(xml, ATTR_USER_ID, item.userId);
	XmlUtils.writeStringAttribute(xml, ATTR_TARGET_PACKAGE_NAME, item.targetPackageName);
	XmlUtils.writeStringAttribute(xml, ATTR_BASE_CODE_PATH, item.baseCodePath);
	XmlUtils.writeIntAttribute(xml, ATTR_STATE, item.state);
	XmlUtils.writeBooleanAttribute(xml, ATTR_IS_ENABLED, item.isEnabled);
	xml.endTag(null, TAG_ITEM);
	}
	}

	private static final class SettingsItem {
	private final int userId;
	private final String packageName;
	private final String targetPackageName;
	private String baseCodePath;
	private int state;
	private boolean isEnabled;
	private OverlayInfo cache;

	SettingsItem(@NonNull final String packageName, final int userId,
	@NonNull final String targetPackageName, @NonNull final String baseCodePath,
	final int state, final boolean isEnabled) {
	this.packageName = packageName;
	this.userId = userId;
	this.targetPackageName = targetPackageName;
	this.baseCodePath = baseCodePath;
	this.state = state;
	this.isEnabled = isEnabled;
	cache = null;
	}

	SettingsItem(@NonNull final String packageName, final int userId,
	@NonNull final String targetPackageName, @NonNull final String baseCodePath) {
	this(packageName, userId, targetPackageName, baseCodePath, STATE_UNKNOWN,
	false);
	}

	private String getTargetPackageName() {
	return targetPackageName;
	}

	private String getBaseCodePath() {
	return baseCodePath;
	}

	private void setBaseCodePath(@NonNull final String path) {
	if (!baseCodePath.equals(path)) {
	baseCodePath = path;
	invalidateCache();
	}
	}

	private int getState() {
	return state;
	}

	private void setState(final int state) {
	if (this.state != state) {
	this.state = state;
	invalidateCache();
	}
	}

	private boolean isEnabled() {
	return isEnabled;
	}

	private void setEnabled(final boolean enable) {
	if (isEnabled != enable) {
	isEnabled = enable;
	invalidateCache();
	}
	}

	private OverlayInfo getOverlayInfo() {
	if (cache == null) {
	cache = new OverlayInfo(packageName, targetPackageName, baseCodePath,
	state, userId);
	}
	return cache;
	}

	private void invalidateCache() {
	cache = null;
	}
	}

	private SettingsItem select(@NonNull final String packageName, final int userId) {
	final int N = mItems.size();
	for (int i = 0; i < N; i++) {
	final SettingsItem item = mItems.get(i);
	if (item.userId == userId && item.packageName.equals(packageName)) {
	return item;
	}
	}
	return null;
	}

	private List<SettingsItem> selectWhereUser(final int userId) {
	final ArrayList<SettingsItem> items = new ArrayList<>();
	final int N = mItems.size();
	for (int i = 0; i < N; i++) {
	final SettingsItem item = mItems.get(i);
	if (item.userId == userId) {
	items.add(item);
	}
	}
	return items;
	}

	private List<SettingsItem> selectWhereTarget(@NonNull final String targetPackageName,
	final int userId) {
	final ArrayList<SettingsItem> items = new ArrayList<>();
	final int N = mItems.size();
	for (int i = 0; i < N; i++) {
	final SettingsItem item = mItems.get(i);
	if (item.userId == userId && item.getTargetPackageName().equals(targetPackageName)) {
	items.add(item);
	}
	}
	return items;
	}

	private void assertNotNull(@Nullable final Object o) {
	if (o == null) {
	throw new AndroidRuntimeException("object must not be null");
	}
	}

	void addChangeListener(@NonNull final ChangeListener listener) {
	mListeners.add(listener);
	}

	void removeChangeListener(@NonNull final ChangeListener listener) {
	mListeners.remove(listener);
	}

	private void notifySettingsChanged() {
	final int N = mListeners.size();
	for (int i = 0; i < N; i++) {
	final ChangeListener listener = mListeners.get(i);
	listener.onSettingsChanged();
	}
	}

	private void notifyOverlayAdded(@NonNull final OverlayInfo oi) {
	if (DEBUG) {
	assertNotNull(oi);
	}
	final int N = mListeners.size();
	for (int i = 0; i < N; i++) {
	final ChangeListener listener = mListeners.get(i);
	listener.onOverlayAdded(oi);
	}
	}

	private void notifyOverlayRemoved(@NonNull final OverlayInfo oi) {
	if (DEBUG) {
	assertNotNull(oi);
	}
	final int N = mListeners.size();
	for (int i = 0; i < N; i++) {
	final ChangeListener listener = mListeners.get(i);
	listener.onOverlayRemoved(oi);
	}
	}

	private void notifyOverlayChanged(@NonNull final OverlayInfo oi,
	@NonNull final OverlayInfo oldOi) {
	if (DEBUG) {
	assertNotNull(oi);
	assertNotNull(oldOi);
	}
	final int N = mListeners.size();
	for (int i = 0; i < N; i++) {
	final ChangeListener listener = mListeners.get(i);
	listener.onOverlayChanged(oi, oldOi);
	}
	}

	private void notifyOverlayPriorityChanged(@NonNull final OverlayInfo oi) {
	if (DEBUG) {
	assertNotNull(oi);
	}
	final int N = mListeners.size();
	for (int i = 0; i < N; i++) {
	final ChangeListener listener = mListeners.get(i);
	listener.onOverlayPriorityChanged(oi);
	}
	}

	interface ChangeListener {
	void onSettingsChanged();
	void onOverlayAdded(@NonNull OverlayInfo oi);
	void onOverlayRemoved(@NonNull OverlayInfo oi);
	void onOverlayChanged(@NonNull OverlayInfo oi, @NonNull OverlayInfo oldOi);
	void onOverlayPriorityChanged(@NonNull OverlayInfo oi);
	}

	static final class BadKeyException extends RuntimeException {
	BadKeyException(@NonNull final String packageName, final int userId) {
	super("Bad key packageName=" + packageName + " userId=" + userId);
	}
	}
	}