content: package com.lody.virtual.server.pm;
  
  import android.app.Activity;
  import android.app.IStopUserCallback;
  import android.content.BroadcastReceiver;
  import android.content.Context;
  import android.content.Intent;
  import android.graphics.Bitmap;
  import android.graphics.BitmapFactory;
  import android.os.Binder;
  import android.util.SparseArray;
  import android.util.Xml;
  
  import com.lody.virtual.R;
  import com.lody.virtual.client.core.VirtualCore;
  import com.lody.virtual.client.env.Constants;
  import com.lody.virtual.helper.compat.ActivityManagerCompat;
  import com.lody.virtual.helper.utils.ArrayUtils;
  import com.lody.virtual.helper.utils.AtomicFile;
  import com.lody.virtual.helper.utils.FastXmlSerializer;
  import com.lody.virtual.helper.utils.VLog;
  import com.lody.virtual.os.VBinder;
  import com.lody.virtual.os.VEnvironment;
  import com.lody.virtual.os.VUserHandle;
  import com.lody.virtual.os.VUserInfo;
  import com.lody.virtual.os.VUserManager;
  import com.lody.virtual.server.am.VActivityManagerService;
  import com.lody.virtual.server.IUserManager;
  
  import org.xmlpull.v1.XmlPullParser;
  import org.xmlpull.v1.XmlPullParserException;
  import org.xmlpull.v1.XmlSerializer;
  
  import java.io.BufferedOutputStream;
  import java.io.File;
  import java.io.FileDescriptor;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  
  
  /**
   * @author Lody
   */
  public class VUserManagerService extends IUserManager.Stub {
  
      private static final String LOG_TAG = "VUserManagerService";
  
      private static final boolean DBG = false;
  
      private static final String TAG_NAME = "name";
      private static final String ATTR_FLAGS = "flags";
      private static final String ATTR_ICON_PATH = "icon";
      private static final String ATTR_ID = "id";
      private static final String ATTR_CREATION_TIME = "created";
      private static final String ATTR_LAST_LOGGED_IN_TIME = "lastLoggedIn";
      private static final String ATTR_SERIAL_NO = "serialNumber";
      private static final String ATTR_NEXT_SERIAL_NO = "nextSerialNumber";
      private static final String ATTR_PARTIAL = "partial";
      private static final String ATTR_USER_VERSION = "version";
      private static final String TAG_USERS = "users";
      private static final String TAG_USER = "user";
  
      private static final String USER_INFO_DIR = "system" + File.separator + "users";
      private static final String USER_LIST_FILENAME = "userlist.xml";
      private static final String USER_PHOTO_FILENAME = "photo.png";
  
      private static final int MIN_USER_ID = 1;
  
      private static final int USER_VERSION = 1;
  
      private static final long EPOCH_PLUS_30_YEARS = 30L * 365 * 24 * 60 * 60 * 1000L; // ms
      private static VUserManagerService sInstance;
      private final Context mContext;
      private final VPackageManagerService mPm;
      private final Object mInstallLock;
      private final Object mPackagesLock;
      private final File mUsersDir;
      private final File mUserListFile;
      private final File mBaseUserPath;
      private SparseArray<VUserInfo> mUsers = new SparseArray<VUserInfo>();
      private HashSet<Integer> mRemovingUserIds = new HashSet<Integer>();
      private int[] mUserIds;
      private boolean mGuestEnabled;
      private int mNextSerialNumber;
      // This resets on a reboot. Otherwise it keeps incrementing so that user ids are
      // not reused in quick succession
      private int mNextUserId = MIN_USER_ID;
      private int mUserVersion = 0;
  
      /**
       * Called by package manager to create the service.  This is closely
       * associated with the package manager, and the given lock is the
       * package manager's own lock.
       */
      VUserManagerService(Context context, VPackageManagerService pm,
                          Object installLock, Object packagesLock) {
          this(context, pm, installLock, packagesLock,
                  VEnvironment.getDataDirectory(),
                  new File(VEnvironment.getDataDirectory(), "user"));
      }
  
      /**
       * Available for testing purposes.
       */
      private VUserManagerService(Context context, VPackageManagerService pm,
                                  Object installLock, Object packagesLock,
                                  File dataDir, File baseUserPath) {
          mContext = context;
          mPm = pm;
          mInstallLock = installLock;
          mPackagesLock = packagesLock;
          synchronized (mInstallLock) {
              synchronized (mPackagesLock) {
                  mUsersDir = new File(dataDir, USER_INFO_DIR);
                  mUsersDir.mkdirs();
                  // Make zeroth user directory, for services to migrate their files to that location
                  File userZeroDir = new File(mUsersDir, "0");
                  userZeroDir.mkdirs();
                  mBaseUserPath = baseUserPath;
  //                FileUtils.setPermissions(mUsersDir.toString(),
  //                        FileUtils.S_IRWXU|FileUtils.S_IRWXG
  //                        |FileUtils.S_IROTH|FileUtils.S_IXOTH,
  //                        -1, -1);
                  mUserListFile = new File(mUsersDir, USER_LIST_FILENAME);
                  readUserListLocked();
                  // Prune out any partially created/partially removed users.
                  ArrayList<VUserInfo> partials = new ArrayList<VUserInfo>();
                  for (int i = 0; i < mUsers.size(); i++) {
                      VUserInfo ui = mUsers.valueAt(i);
                      if (ui.partial && i != 0) {
                          partials.add(ui);
                      }
                  }
                  for (int i = 0; i < partials.size(); i++) {
                      VUserInfo ui = partials.get(i);
                      VLog.w(LOG_TAG, "Removing partially created user #" + i
                              + " (name=" + ui.name + ")");
                      removeUserStateLocked(ui.id);
                  }
                  sInstance = this;
              }
          }
      }
  
      public static VUserManagerService get() {
          synchronized (VUserManagerService.class) {
              return sInstance;
          }
      }
  
      /**
       * Enforces that only the system UID or root's UID or apps that have the
       * {android.Manifest.permission.MANAGE_USERS MANAGE_USERS}
       * permission can make certain calls to the VUserManager.
       *
       * @param message used as message if SecurityException is thrown
       * @throws SecurityException if the caller is not system or root
       */
      private static void checkManageUsersPermission(String message) {
          final int uid = VBinder.getCallingUid();
          if (uid != VirtualCore.get().myUid()) {
              throw new SecurityException("You need MANAGE_USERS permission to: " + message);
          }
      }
  
      @Override
      public List<VUserInfo> getUsers(boolean excludeDying) {
          //checkManageUsersPermission("query users");
          synchronized (mPackagesLock) {
              ArrayList<VUserInfo> users = new ArrayList<VUserInfo>(mUsers.size());
              for (int i = 0; i < mUsers.size(); i++) {
                  VUserInfo ui = mUsers.valueAt(i);
                  if (ui.partial) {
                      continue;
                  }
                  if (!excludeDying || !mRemovingUserIds.contains(ui.id)) {
                      users.add(ui);
                  }
              }
              return users;
          }
      }
  
      @Override
      public VUserInfo getUserInfo(int userId) {
          //checkManageUsersPermission("query user");
          synchronized (mPackagesLock) {
              return getUserInfoLocked(userId);
          }
      }
  
      /*
       * Should be locked on mUsers before calling this.
       */
      private VUserInfo getUserInfoLocked(int userId) {
          VUserInfo ui = mUsers.get(userId);
          // If it is partial and not in the process of being removed, return as unknown user.
          if (ui != null && ui.partial && !mRemovingUserIds.contains(userId)) {
              VLog.w(LOG_TAG, "getUserInfo: unknown user #" + userId);
              return null;
          }
          return ui;
      }
  
      public boolean exists(int userId) {
          synchronized (mPackagesLock) {
              return ArrayUtils.contains(mUserIds, userId);
          }
      }
  
      @Override
      public void setUserName(int userId, String name) {
          checkManageUsersPermission("rename users");
          boolean changed = false;
          synchronized (mPackagesLock) {
              VUserInfo info = mUsers.get(userId);
              if (info == null || info.partial) {
                  VLog.w(LOG_TAG, "setUserName: unknown user #" + userId);
                  return;
              }
              if (name != null && !name.equals(info.name)) {
                  info.name = name;
                  writeUserLocked(info);
                  changed = true;
              }
          }
          if (changed) {
              sendUserInfoChangedBroadcast(userId);
          }
      }
  
      @Override
      public void setUserIcon(int userId, Bitmap bitmap) {
          checkManageUsersPermission("update users");
          synchronized (mPackagesLock) {
              VUserInfo info = mUsers.get(userId);
              if (info == null || info.partial) {
                  VLog.w(LOG_TAG, "setUserIcon: unknown user #" + userId);
                  return;
              }
              writeBitmapLocked(info, bitmap);
              writeUserLocked(info);
          }
          sendUserInfoChangedBroadcast(userId);
      }
  
      private void sendUserInfoChangedBroadcast(int userId) {
          Intent changedIntent = new Intent(Constants.ACTION_USER_INFO_CHANGED);
          changedIntent.putExtra(Constants.EXTRA_USER_HANDLE, userId);
          changedIntent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
          VActivityManagerService.get().sendBroadcastAsUser(changedIntent, new VUserHandle(userId));
      }
  
      @Override
      public Bitmap getUserIcon(int userId) {
          //checkManageUsersPermission("read users");
          synchronized (mPackagesLock) {
              VUserInfo info = mUsers.get(userId);
              if (info == null || info.partial) {
                  VLog.w(LOG_TAG, "getUserIcon: unknown user #" + userId);
                  return null;
              }
              if (info.iconPath == null) {
                  return null;
              }
              return BitmapFactory.decodeFile(info.iconPath);
          }
      }
  
      @Override
      public boolean isGuestEnabled() {
          synchronized (mPackagesLock) {
              return mGuestEnabled;
          }
      }
  
      @Override
      public void setGuestEnabled(boolean enable) {
          checkManageUsersPermission("enable guest users");
          synchronized (mPackagesLock) {
              if (mGuestEnabled != enable) {
                  mGuestEnabled = enable;
                  // Erase any guest user that currently exists
                  for (int i = 0; i < mUsers.size(); i++) {
                      VUserInfo user = mUsers.valueAt(i);
                      if (!user.partial && user.isGuest()) {
                          if (!enable) {
                              removeUser(user.id);
                          }
                          return;
                      }
                  }
                  // No guest was found
                  if (enable) {
                      createUser("Guest", VUserInfo.FLAG_GUEST);
                  }
              }
          }
      }
  
      @Override
      public void wipeUser(int userHandle) {
          checkManageUsersPermission("wipe user");
          // TODO:
      }
  
      public void makeInitialized(int userId) {
          checkManageUsersPermission("makeInitialized");
          synchronized (mPackagesLock) {
              VUserInfo info = mUsers.get(userId);
              if (info == null || info.partial) {
                  VLog.w(LOG_TAG, "makeInitialized: unknown user #" + userId);
              }
              if ((info.flags& VUserInfo.FLAG_INITIALIZED) == 0) {
                  info.flags |= VUserInfo.FLAG_INITIALIZED;
                  writeUserLocked(info);
              }
          }
      }
  
      /**
       * Check if we've hit the limit of how many users can be created.
       */
      private boolean isUserLimitReachedLocked() {
          int nUsers = mUsers.size();
          return nUsers >= VUserManager.getMaxSupportedUsers();
      }
  
      private void writeBitmapLocked(VUserInfo info, Bitmap bitmap) {
          try {
              File dir = new File(mUsersDir, Integer.toString(info.id));
              File file = new File(dir, USER_PHOTO_FILENAME);
              if (!dir.exists()) {
                  dir.mkdir();
  //                FileUtils.setPermissions(
  //                        dir.getPath(),
  //                        FileUtils.S_IRWXU|FileUtils.S_IRWXG|FileUtils.S_IXOTH,
  //                        -1, -1);
              }
              FileOutputStream os;
              if (bitmap.compress(Bitmap.CompressFormat.PNG, 100, os = new FileOutputStream(file))) {
                  info.iconPath = file.getAbsolutePath();
              }
              try {
                  os.close();
              } catch (IOException ioe) {
                  // What the ... !
              }
          } catch (FileNotFoundException e) {
              VLog.w(LOG_TAG, "Error setting photo for user ", e);
          }
      }
  
      /**
       * Returns an array of user ids. This array is cached here for quick access, so do not modify or
       * cache it elsewhere.
       * @return the array of user ids.
       */
      public int[] getUserIds() {
          synchronized (mPackagesLock) {
              return mUserIds;
          }
      }
  
      int[] getUserIdsLPr() {
          return mUserIds;
      }
  
      private void readUserList() {
          synchronized (mPackagesLock) {
              readUserListLocked();
          }
      }
  
      private void readUserListLocked() {
          mGuestEnabled = false;
          if (!mUserListFile.exists()) {
              fallbackToSingleUserLocked();
              return;
          }
          FileInputStream fis = null;
          AtomicFile userListFile = new AtomicFile(mUserListFile);
          try {
              fis = userListFile.openRead();
              XmlPullParser parser = Xml.newPullParser();
              parser.setInput(fis, null);
              int type;
              while ((type = parser.next()) != XmlPullParser.START_TAG
                      && type != XmlPullParser.END_DOCUMENT) {
                  ;
              }
  
              if (type != XmlPullParser.START_TAG) {
                  VLog.e(LOG_TAG, "Unable to read user list");
                  fallbackToSingleUserLocked();
                  return;
              }
  
              mNextSerialNumber = -1;
              if (parser.getName().equals(TAG_USERS)) {
                  String lastSerialNumber = parser.getAttributeValue(null, ATTR_NEXT_SERIAL_NO);
                  if (lastSerialNumber != null) {
                      mNextSerialNumber = Integer.parseInt(lastSerialNumber);
                  }
                  String versionNumber = parser.getAttributeValue(null, ATTR_USER_VERSION);
                  if (versionNumber != null) {
                      mUserVersion = Integer.parseInt(versionNumber);
                  }
              }
  
              while ((type = parser.next()) != XmlPullParser.END_DOCUMENT) {
                  if (type == XmlPullParser.START_TAG && parser.getName().equals(TAG_USER)) {
                      String id = parser.getAttributeValue(null, ATTR_ID);
                      VUserInfo user = readUser(Integer.parseInt(id));
  
                      if (user != null) {
                          mUsers.put(user.id, user);
                          if (user.isGuest()) {
                              mGuestEnabled = true;
                          }
                          if (mNextSerialNumber < 0 || mNextSerialNumber <= user.id) {
                              mNextSerialNumber = user.id + 1;
                          }
                      }
                  }
              }
              updateUserIdsLocked();
              upgradeIfNecessary();
          } catch (IOException ioe) {
              fallbackToSingleUserLocked();
          } catch (XmlPullParserException pe) {
              fallbackToSingleUserLocked();
          } finally {
              if (fis != null) {
                  try {
                      fis.close();
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              }
          }
      }
  
      /**
       * This fixes an incorrect initialization of user name for the owner.
       * TODO: Remove in the next release.
       */
      private void upgradeIfNecessary() {
          int userVersion = mUserVersion;
          if (userVersion < 1) {
              // Assign a proper name for the owner, if not initialized correctly before
              VUserInfo user = mUsers.get(VUserHandle.USER_OWNER);
              if ("Primary".equals(user.name)) {
                  user.name = "Admin";
                  writeUserLocked(user);
              }
              userVersion = 1;
          }
  
          if (userVersion < USER_VERSION) {
              VLog.w(LOG_TAG, "User version " + mUserVersion + " didn't upgrade as expected to "
                      + USER_VERSION);
          } else {
              mUserVersion = userVersion;
              writeUserListLocked();
          }
      }
  
      private void fallbackToSingleUserLocked() {
          // Create the primary user
          VUserInfo primary = new VUserInfo(0,
                  mContext.getResources().getString(R.string.owner_name), null,
                  VUserInfo.FLAG_ADMIN | VUserInfo.FLAG_PRIMARY | VUserInfo.FLAG_INITIALIZED);
          mUsers.put(0, primary);
          mNextSerialNumber = MIN_USER_ID;
          updateUserIdsLocked();
  
          writeUserListLocked();
          writeUserLocked(primary);
      }
  
      /*
       * Writes the user file in this format:
       *
       * <user flags="20039023" id="0">
       *   <name>Primary</name>
       * </user>
       */
      private void writeUserLocked(VUserInfo userInfo) {
          FileOutputStream fos = null;
          AtomicFile userFile = new AtomicFile(new File(mUsersDir, userInfo.id + ".xml"));
          try {
              fos = userFile.startWrite();
              final BufferedOutputStream bos = new BufferedOutputStream(fos);
  
              // XmlSerializer serializer = XmlUtils.serializerInstance();
              final XmlSerializer serializer = new FastXmlSerializer();
              serializer.setOutput(bos, "utf-8");
              serializer.startDocument(null, true);
              serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
  
              serializer.startTag(null, TAG_USER);
              serializer.attribute(null, ATTR_ID, Integer.toString(userInfo.id));
              serializer.attribute(null, ATTR_SERIAL_NO, Integer.toString(userInfo.serialNumber));
              serializer.attribute(null, ATTR_FLAGS, Integer.toString(userInfo.flags));
              serializer.attribute(null, ATTR_CREATION_TIME, Long.toString(userInfo.creationTime));
              serializer.attribute(null, ATTR_LAST_LOGGED_IN_TIME,
                      Long.toString(userInfo.lastLoggedInTime));
              if (userInfo.iconPath != null) {
                  serializer.attribute(null,  ATTR_ICON_PATH, userInfo.iconPath);
              }
              if (userInfo.partial) {
                  serializer.attribute(null, ATTR_PARTIAL, "true");
              }
  
              serializer.startTag(null, TAG_NAME);
              serializer.text(userInfo.name);
              serializer.endTag(null, TAG_NAME);
  
              serializer.endTag(null, TAG_USER);
  
              serializer.endDocument();
              userFile.finishWrite(fos);
          } catch (Exception ioe) {
              VLog.e(LOG_TAG, "Error writing user info " + userInfo.id + "\n" + ioe);
              userFile.failWrite(fos);
          }
      }
  
      /*
       * Writes the user list file in this format:
       *
       * <users nextSerialNumber="3">
       *   <user id="0"></user>
       *   <user id="2"></user>
       * </users>
       */
      private void writeUserListLocked() {
          FileOutputStream fos = null;
          AtomicFile userListFile = new AtomicFile(mUserListFile);
          try {
              fos = userListFile.startWrite();
              final BufferedOutputStream bos = new BufferedOutputStream(fos);
  
              // XmlSerializer serializer = XmlUtils.serializerInstance();
              final XmlSerializer serializer = new FastXmlSerializer();
              serializer.setOutput(bos, "utf-8");
              serializer.startDocument(null, true);
              serializer.setFeature("http://xmlpull.org/v1/doc/features.html#indent-output", true);
  
              serializer.startTag(null, TAG_USERS);
              serializer.attribute(null, ATTR_NEXT_SERIAL_NO, Integer.toString(mNextSerialNumber));
              serializer.attribute(null, ATTR_USER_VERSION, Integer.toString(mUserVersion));
  
              for (int i = 0; i < mUsers.size(); i++) {
                  VUserInfo user = mUsers.valueAt(i);
                  serializer.startTag(null, TAG_USER);
                  serializer.attribute(null, ATTR_ID, Integer.toString(user.id));
                  serializer.endTag(null, TAG_USER);
              }
  
              serializer.endTag(null, TAG_USERS);
  
              serializer.endDocument();
              userListFile.finishWrite(fos);
          } catch (Exception e) {
              userListFile.failWrite(fos);
              VLog.e(LOG_TAG, "Error writing user list");
          }
      }
  
      private VUserInfo readUser(int id) {
          int flags = 0;
          int serialNumber = id;
          String name = null;
          String iconPath = null;
          long creationTime = 0L;
          long lastLoggedInTime = 0L;
          boolean partial = false;
  
          FileInputStream fis = null;
          try {
              AtomicFile userFile =
                      new AtomicFile(new File(mUsersDir, Integer.toString(id) + ".xml"));
              fis = userFile.openRead();
              XmlPullParser parser = Xml.newPullParser();
              parser.setInput(fis, null);
              int type;
              while ((type = parser.next()) != XmlPullParser.START_TAG
                      && type != XmlPullParser.END_DOCUMENT) {
                  ;
              }
  
              if (type != XmlPullParser.START_TAG) {
                  VLog.e(LOG_TAG, "Unable to read user " + id);
                  return null;
              }
  
              if (parser.getName().equals(TAG_USER)) {
                  int storedId = readIntAttribute(parser, ATTR_ID, -1);
                  if (storedId != id) {
                      VLog.e(LOG_TAG, "User id does not match the file name");
                      return null;
                  }
                  serialNumber = readIntAttribute(parser, ATTR_SERIAL_NO, id);
                  flags = readIntAttribute(parser, ATTR_FLAGS, 0);
                  iconPath = parser.getAttributeValue(null, ATTR_ICON_PATH);
                  creationTime = readLongAttribute(parser, ATTR_CREATION_TIME, 0);
                  lastLoggedInTime = readLongAttribute(parser, ATTR_LAST_LOGGED_IN_TIME, 0);
                  String valueString = parser.getAttributeValue(null, ATTR_PARTIAL);
                  if ("true".equals(valueString)) {
                      partial = true;
                  }
  
                  while ((type = parser.next()) != XmlPullParser.START_TAG
                          && type != XmlPullParser.END_DOCUMENT) {
                  }
                  if (type == XmlPullParser.START_TAG && parser.getName().equals(TAG_NAME)) {
                      type = parser.next();
                      if (type == XmlPullParser.TEXT) {
                          name = parser.getText();
                      }
                  }
              }
  
              VUserInfo userInfo = new VUserInfo(id, name, iconPath, flags);
              userInfo.serialNumber = serialNumber;
              userInfo.creationTime = creationTime;
              userInfo.lastLoggedInTime = lastLoggedInTime;
              userInfo.partial = partial;
              return userInfo;
  
          } catch (IOException ioe) {
          } catch (XmlPullParserException pe) {
          } finally {
              if (fis != null) {
                  try {
                      fis.close();
                  } catch (IOException e) {
                  }
              }
          }
          return null;
      }
  
      private int readIntAttribute(XmlPullParser parser, String attr, int defaultValue) {
          String valueString = parser.getAttributeValue(null, attr);
          if (valueString == null) return defaultValue;
          try {
              return Integer.parseInt(valueString);
          } catch (NumberFormatException nfe) {
              return defaultValue;
          }
      }
  
      private long readLongAttribute(XmlPullParser parser, String attr, long defaultValue) {
          String valueString = parser.getAttributeValue(null, attr);
          if (valueString == null) return defaultValue;
          try {
              return Long.parseLong(valueString);
          } catch (NumberFormatException nfe) {
              return defaultValue;
          }
      }
  
      @Override
      public VUserInfo createUser(String name, int flags) {
          checkManageUsersPermission("Only the system can create users");
  
          final long ident = Binder.clearCallingIdentity();
          final VUserInfo userInfo;
          try {
              synchronized (mInstallLock) {
                  synchronized (mPackagesLock) {
                      if (isUserLimitReachedLocked()) return null;
                      int userId = getNextAvailableIdLocked();
                      userInfo = new VUserInfo(userId, name, null, flags);
                      File userPath = new File(mBaseUserPath, Integer.toString(userId));
                      userInfo.serialNumber = mNextSerialNumber++;
                      long now = System.currentTimeMillis();
                      userInfo.creationTime = (now > EPOCH_PLUS_30_YEARS) ? now : 0;
                      userInfo.partial = true;
                      VEnvironment.getUserSystemDirectory(userInfo.id).mkdirs();
                      mUsers.put(userId, userInfo);
                      writeUserListLocked();
                      writeUserLocked(userInfo);
                      mPm.createNewUser(userId, userPath);
                      userInfo.partial = false;
                      writeUserLocked(userInfo);
                      updateUserIdsLocked();
                  }
              }
              Intent addedIntent = new Intent(Constants.ACTION_USER_ADDED);
              addedIntent.putExtra(Constants.EXTRA_USER_HANDLE, userInfo.id);
              VActivityManagerService.get().sendBroadcastAsUser(addedIntent, VUserHandle.ALL,
                          null);
          } finally {
              Binder.restoreCallingIdentity(ident);
          }
          return userInfo;
      }
  
      /**
       * Removes a user and all data directories created for that user. This method should be called
       * after the user's processes have been terminated.
       * @param userHandle the user's id
       */
      public boolean removeUser(int userHandle) {
          checkManageUsersPermission("Only the system can remove users");
          final VUserInfo user;
          synchronized (mPackagesLock) {
              user = mUsers.get(userHandle);
              if (userHandle == 0 || user == null) {
                  return false;
              }
              mRemovingUserIds.add(userHandle);
              // Set this to a partially created user, so that the user will be purged
              // on next startup, in case the runtime stops now before stopping and
              // removing the user completely.
              user.partial = true;
              writeUserLocked(user);
          }
          if (DBG) VLog.i(LOG_TAG, "Stopping user " + userHandle);
          int res = VActivityManagerService.get().stopUser(userHandle,
                      new IStopUserCallback.Stub() {
                          @Override
                          public void userStopped(int userId) {
                              finishRemoveUser(userId);
                          }
                          @Override
                          public void userStopAborted(int userId) {
                          }
              });
          return res == ActivityManagerCompat.USER_OP_SUCCESS;
      }
  
      void finishRemoveUser(final int userHandle) {
          if (DBG) VLog.i(LOG_TAG, "finishRemoveUser " + userHandle);
          // Let other services shutdown any activity and clean up their state before completely
          // wiping the user's system directory and removing from the user list
          long identity = Binder.clearCallingIdentity();
          try {
              Intent addedIntent = new Intent(Constants.ACTION_USER_REMOVED);
              addedIntent.putExtra(Constants.EXTRA_USER_HANDLE, userHandle);
              VActivityManagerService.get().sendOrderedBroadcastAsUser(addedIntent, VUserHandle.ALL,
                     null,
                      new BroadcastReceiver() {
                          @Override
                          public void onReceive(Context context, Intent intent) {
                              if (DBG) {
                                  VLog.i(LOG_TAG,
                                          "USER_REMOVED broadcast sent, cleaning up user data "
                                          + userHandle);
                              }
                              new Thread() {
                                  public void run() {
                                      synchronized (mInstallLock) {
                                          synchronized (mPackagesLock) {
                                              removeUserStateLocked(userHandle);
                                          }
                                      }
                                  }
                              }.start();
                          }
                      },
                      null, Activity.RESULT_OK, null, null);
          } finally {
              Binder.restoreCallingIdentity(identity);
          }
      }
  
      private void removeUserStateLocked(int userHandle) {
          // Cleanup package manager settings
          mPm.cleanUpUser(userHandle);
  
          // Remove this user from the list
          mUsers.remove(userHandle);
          mRemovingUserIds.remove(userHandle);
          // Remove user file
          AtomicFile userFile = new AtomicFile(new File(mUsersDir, userHandle + ".xml"));
          userFile.delete();
          // Update the user list
          writeUserListLocked();
          updateUserIdsLocked();
          removeDirectoryRecursive(VEnvironment.getUserSystemDirectory(userHandle));
      }
  
      private void removeDirectoryRecursive(File parent) {
          if (parent.isDirectory()) {
              String[] files = parent.list();
              for (String filename : files) {
                  File child = new File(parent, filename);
                  removeDirectoryRecursive(child);
              }
          }
          parent.delete();
      }
  
      @Override
      public int getUserSerialNumber(int userHandle) {
          synchronized (mPackagesLock) {
              if (!exists(userHandle)) return -1;
              return getUserInfoLocked(userHandle).serialNumber;
          }
      }
  
      @Override
      public int getUserHandle(int userSerialNumber) {
          synchronized (mPackagesLock) {
              for (int userId : mUserIds) {
                  if (getUserInfoLocked(userId).serialNumber == userSerialNumber) return userId;
              }
              // Not found
              return -1;
          }
      }
  
      /**
       * Caches the list of user ids in an array, adjusting the array size when necessary.
       */
      private void updateUserIdsLocked() {
          int num = 0;
          for (int i = 0; i < mUsers.size(); i++) {
              if (!mUsers.valueAt(i).partial) {
                  num++;
              }
          }
          final int[] newUsers = new int[num];
          int n = 0;
          for (int i = 0; i < mUsers.size(); i++) {
              if (!mUsers.valueAt(i).partial) {
                  newUsers[n++] = mUsers.keyAt(i);
              }
          }
          mUserIds = newUsers;
      }
  
      /**
       * Make a note of the last started time of a user.
       * @param userId the user that was just foregrounded
       */
      public void userForeground(int userId) {
          synchronized (mPackagesLock) {
              VUserInfo user = mUsers.get(userId);
              long now = System.currentTimeMillis();
              if (user == null || user.partial) {
                  VLog.w(LOG_TAG, "userForeground: unknown user #" + userId);
                  return;
              }
              if (now > EPOCH_PLUS_30_YEARS) {
                  user.lastLoggedInTime = now;
                  writeUserLocked(user);
              }
          }
      }
  
      /**
       * Returns the next available user id, filling in any holes in the ids.
       * TODO: May not be a good idea to recycle ids, in case it results in confusion
       * for data and battery stats collection, or unexpected cross-talk.
       * @return
       */
      private int getNextAvailableIdLocked() {
          synchronized (mPackagesLock) {
              int i = mNextUserId;
              while (i < Integer.MAX_VALUE) {
                  if (mUsers.indexOfKey(i) < 0 && !mRemovingUserIds.contains(i)) {
                      break;
                  }
                  i++;
              }
              mNextUserId = i + 1;
              return i;
          }
      }
  
      @Override
      protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
  
      }
  }
  