content: /*
   * Copyright (C) 2010 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 android.mtp;
  
  import com.android.internal.util.Preconditions;
  
  import android.content.Context;
  import android.content.SharedPreferences;
  import android.util.ByteStringUtils;
  
  import java.io.FileDescriptor;
  import java.util.Random;
  
  /**
   * Java wrapper for MTP/PTP support as USB responder.
   * {@hide}
   */
  public class MtpServer implements Runnable {
  
      private long mNativeContext; // accessed by native methods
      private final MtpDatabase mDatabase;
      private final Runnable mOnTerminate;
      private final Context mContext;
  
  // It requires "exactly 32 characters, including any leading 0s" in MTP spec
  // (5.1.1.14 Serial Number)
      private static final int sID_LEN_BYTES = 16;
      private static final int sID_LEN_STR = (sID_LEN_BYTES * 2);
  
      static {
          System.loadLibrary("media_jni");
      }
  
      public MtpServer(
              MtpDatabase database,
              FileDescriptor controlFd,
              boolean usePtp,
              Runnable onTerminate,
              String deviceInfoManufacturer,
              String deviceInfoModel,
              String deviceInfoDeviceVersion) {
          mDatabase = Preconditions.checkNotNull(database);
          mOnTerminate = Preconditions.checkNotNull(onTerminate);
          mContext = mDatabase.getContext();
  
          final String strID_PREFS_NAME = "mtp-cfg";
          final String strID_PREFS_KEY = "mtp-id";
          String strRandomId = null;
          String deviceInfoSerialNumber;
  
          SharedPreferences sharedPref =
                  mContext.getSharedPreferences(strID_PREFS_NAME, Context.MODE_PRIVATE);
          if (sharedPref.contains(strID_PREFS_KEY)) {
              strRandomId = sharedPref.getString(strID_PREFS_KEY, null);
  
              // Check for format consistence (regenerate upon corruption)
              if (strRandomId.length() != sID_LEN_STR) {
                  strRandomId = null;
              } else {
                  // Only accept hex digit
                  for (int ii = 0; ii < strRandomId.length(); ii++)
                      if (Character.digit(strRandomId.charAt(ii), 16) == -1) {
                          strRandomId = null;
                          break;
                      }
              }
          }
  
          if (strRandomId == null) {
              strRandomId = getRandId();
              sharedPref.edit().putString(strID_PREFS_KEY, strRandomId).apply();
          }
  
          deviceInfoSerialNumber = strRandomId;
  
          native_setup(
                  database,
                  controlFd,
                  usePtp,
                  deviceInfoManufacturer,
                  deviceInfoModel,
                  deviceInfoDeviceVersion,
                  deviceInfoSerialNumber);
          database.setServer(this);
      }
  
      private String getRandId() {
          Random randomVal = new Random();
          byte[] randomBytes = new byte[sID_LEN_BYTES];
  
          randomVal.nextBytes(randomBytes);
          return ByteStringUtils.toHexString(randomBytes);
      }
  
      public void start() {
          Thread thread = new Thread(this, "MtpServer");
          thread.start();
      }
  
      @Override
      public void run() {
          native_run();
          native_cleanup();
          mDatabase.close();
          mOnTerminate.run();
      }
  
      public void sendObjectAdded(int handle) {
          native_send_object_added(handle);
      }
  
      public void sendObjectRemoved(int handle) {
          native_send_object_removed(handle);
      }
  
      public void sendObjectInfoChanged(int handle) {
          native_send_object_info_changed(handle);
      }
  
      public void sendDevicePropertyChanged(int property) {
          native_send_device_property_changed(property);
      }
  
      public void addStorage(MtpStorage storage) {
          native_add_storage(storage);
      }
  
      public void removeStorage(MtpStorage storage) {
          native_remove_storage(storage.getStorageId());
      }
  
      public static void configure(boolean usePtp) {
          native_configure(usePtp);
      }
  
      public static native final void native_configure(boolean usePtp);
      private native final void native_setup(
              MtpDatabase database,
              FileDescriptor controlFd,
              boolean usePtp,
              String deviceInfoManufacturer,
              String deviceInfoModel,
              String deviceInfoDeviceVersion,
              String deviceInfoSerialNumber);
      private native final void native_run();
      private native final void native_cleanup();
      private native final void native_send_object_added(int handle);
      private native final void native_send_object_removed(int handle);
      private native final void native_send_object_info_changed(int handle);
      private native final void native_send_device_property_changed(int property);
      private native final void native_add_storage(MtpStorage storage);
      private native final void native_remove_storage(int storageId);
  }
  