code: package com.lody.virtual.server.vs;
  
  import android.os.RemoteException;
  import android.util.SparseArray;
  
  import com.lody.virtual.server.interfaces.IVirtualStorageService;
  import com.lody.virtual.server.pm.VUserManagerService;
  
  import java.util.HashMap;
  
  /**
   * @author Lody
   */
  
  public class VirtualStorageService implements IVirtualStorageService {
  
      private static final VirtualStorageService sService = new VirtualStorageService();
      private final VSPersistenceLayer mLayer = new VSPersistenceLayer(this);
      private final SparseArray<HashMap<String, VSConfig>> mConfigs = new SparseArray<>();
  
      public static VirtualStorageService get() {
          return sService;
      }
  
      private VirtualStorageService() {
          mLayer.read();
      }
  
      SparseArray<HashMap<String, VSConfig>> getConfigs() {
          return mConfigs;
      }
  
      @Override
      public void setVirtualStorage(String packageName, int userId, String vsPath) {
          checkUserId(userId);
          synchronized (mConfigs) {
              VSConfig config = getOrCreateVSConfigLocked(packageName, userId);
              config.vsPath = vsPath;
              mLayer.save();
          }
      }
  
      private VSConfig getOrCreateVSConfigLocked(String packageName, int userId) {
          HashMap<String, VSConfig> userMap = mConfigs.get(userId);
          if (userMap == null) {
              userMap = new HashMap<>();
              mConfigs.put(userId, userMap);
          }
          VSConfig config = userMap.get(packageName);
          if (config == null) {
              config = new VSConfig();
              config.enable = true;
              userMap.put(packageName, config);
          }
          return config;
      }
  
  
      @Override
      public String getVirtualStorage(String packageName, int userId) {
          checkUserId(userId);
          synchronized (mConfigs) {
              VSConfig config = getOrCreateVSConfigLocked(packageName, userId);
              return config.vsPath;
          }
      }
  
      @Override
      public void setVirtualStorageState(String packageName, int userId, boolean enable) {
          checkUserId(userId);
          synchronized (mConfigs) {
              VSConfig config = getOrCreateVSConfigLocked(packageName, userId);
              config.enable = enable;
              mLayer.save();
          }
  
      }
  
      @Override
      public boolean isVirtualStorageEnable(String packageName, int userId) {
          checkUserId(userId);
          synchronized (mConfigs) {
              VSConfig config = getOrCreateVSConfigLocked(packageName, userId);
              return config.enable;
          }
  
      }
  
      private void checkUserId(int userId) {
          if (!VUserManagerService.get().exists(userId)) {
              throw new IllegalStateException("Invalid userId " + userId);
          }
      }
  }
  