content: /*
   * Copyright 2009-2016 The Android Open Source Project
   * Copyright 2015 Samsung LSI
   *
   * 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.bluetooth;
  
  import android.Manifest;
  import android.annotation.IntDef;
  import android.annotation.NonNull;
  import android.annotation.Nullable;
  import android.annotation.RequiresPermission;
  import android.annotation.SdkConstant;
  import android.annotation.SdkConstant.SdkConstantType;
  import android.annotation.SystemApi;
  import android.annotation.UnsupportedAppUsage;
  import android.app.ActivityThread;
  import android.bluetooth.le.BluetoothLeAdvertiser;
  import android.bluetooth.le.BluetoothLeScanner;
  import android.bluetooth.le.PeriodicAdvertisingManager;
  import android.bluetooth.le.ScanCallback;
  import android.bluetooth.le.ScanFilter;
  import android.bluetooth.le.ScanRecord;
  import android.bluetooth.le.ScanResult;
  import android.bluetooth.le.ScanSettings;
  import android.content.Context;
  import android.os.BatteryStats;
  import android.os.Binder;
  import android.os.IBinder;
  import android.os.ParcelUuid;
  import android.os.RemoteException;
  import android.os.ResultReceiver;
  import android.os.ServiceManager;
  import android.os.SynchronousResultReceiver;
  import android.os.SystemProperties;
  import android.util.Log;
  import android.util.Pair;
  
  import java.io.IOException;
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.Set;
  import java.util.UUID;
  import java.util.concurrent.Executor;
  import java.util.concurrent.TimeoutException;
  import java.util.concurrent.locks.ReentrantReadWriteLock;
  
  /**
   * Represents the local device Bluetooth adapter. The {@link BluetoothAdapter}
   * lets you perform fundamental Bluetooth tasks, such as initiate
   * device discovery, query a list of bonded (paired) devices,
   * instantiate a {@link BluetoothDevice} using a known MAC address, and create
   * a {@link BluetoothServerSocket} to listen for connection requests from other
   * devices, and start a scan for Bluetooth LE devices.
   *
   * <p>To get a {@link BluetoothAdapter} representing the local Bluetooth
   * adapter, call the {@link BluetoothManager#getAdapter} function on {@link BluetoothManager}.
   * On JELLY_BEAN_MR1 and below you will need to use the static {@link #getDefaultAdapter}
   * method instead.
   * </p><p>
   * Fundamentally, this is your starting point for all
   * Bluetooth actions. Once you have the local adapter, you can get a set of
   * {@link BluetoothDevice} objects representing all paired devices with
   * {@link #getBondedDevices()}; start device discovery with
   * {@link #startDiscovery()}; or create a {@link BluetoothServerSocket} to
   * listen for incoming RFComm connection requests with {@link
   * #listenUsingRfcommWithServiceRecord(String, UUID)}; listen for incoming L2CAP Connection-oriented
   * Channels (CoC) connection requests with {@link #listenUsingL2capChannel()}; or start a scan for
   * Bluetooth LE devices with {@link #startLeScan(LeScanCallback callback)}.
   * </p>
   * <p>This class is thread safe.</p>
   * <p class="note"><strong>Note:</strong>
   * Most methods require the {@link android.Manifest.permission#BLUETOOTH}
   * permission and some also require the
   * {@link android.Manifest.permission#BLUETOOTH_ADMIN} permission.
   * </p>
   * <div class="special reference">
   * <h3>Developer Guides</h3>
   * <p>
   * For more information about using Bluetooth, read the <a href=
   * "{@docRoot}guide/topics/connectivity/bluetooth.html">Bluetooth</a> developer
   * guide.
   * </p>
   * </div>
   *
   * {@see BluetoothDevice}
   * {@see BluetoothServerSocket}
   */
  public final class BluetoothAdapter {
      private static final String TAG = "BluetoothAdapter";
      private static final boolean DBG = true;
      private static final boolean VDBG = false;
  
      /**
       * Default MAC address reported to a client that does not have the
       * android.permission.LOCAL_MAC_ADDRESS permission.
       *
       * @hide
       */
      public static final String DEFAULT_MAC_ADDRESS = "02:00:00:00:00:00";
  
      /**
       * Sentinel error value for this class. Guaranteed to not equal any other
       * integer constant in this class. Provided as a convenience for functions
       * that require a sentinel error value, for example:
       * <p><code>Intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,
       * BluetoothAdapter.ERROR)</code>
       */
      public static final int ERROR = Integer.MIN_VALUE;
  
      /**
       * Broadcast Action: The state of the local Bluetooth adapter has been
       * changed.
       * <p>For example, Bluetooth has been turned on or off.
       * <p>Always contains the extra fields {@link #EXTRA_STATE} and {@link
       * #EXTRA_PREVIOUS_STATE} containing the new and old states
       * respectively.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH} to receive.
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION) public static final String
              ACTION_STATE_CHANGED = "android.bluetooth.adapter.action.STATE_CHANGED";
  
      /**
       * Used as an int extra field in {@link #ACTION_STATE_CHANGED}
       * intents to request the current power state. Possible values are:
       * {@link #STATE_OFF},
       * {@link #STATE_TURNING_ON},
       * {@link #STATE_ON},
       * {@link #STATE_TURNING_OFF},
       */
      public static final String EXTRA_STATE = "android.bluetooth.adapter.extra.STATE";
      /**
       * Used as an int extra field in {@link #ACTION_STATE_CHANGED}
       * intents to request the previous power state. Possible values are:
       * {@link #STATE_OFF},
       * {@link #STATE_TURNING_ON},
       * {@link #STATE_ON},
       * {@link #STATE_TURNING_OFF}
       */
      public static final String EXTRA_PREVIOUS_STATE =
              "android.bluetooth.adapter.extra.PREVIOUS_STATE";
  
      /** @hide */
      @IntDef(prefix = { "STATE_" }, value = {
              STATE_OFF,
              STATE_TURNING_ON,
              STATE_ON,
              STATE_TURNING_OFF,
              STATE_BLE_TURNING_ON,
              STATE_BLE_ON,
              STATE_BLE_TURNING_OFF
      })
      @Retention(RetentionPolicy.SOURCE)
      public @interface AdapterState {}
  
      /**
       * Indicates the local Bluetooth adapter is off.
       */
      public static final int STATE_OFF = 10;
      /**
       * Indicates the local Bluetooth adapter is turning on. However local
       * clients should wait for {@link #STATE_ON} before attempting to
       * use the adapter.
       */
      public static final int STATE_TURNING_ON = 11;
      /**
       * Indicates the local Bluetooth adapter is on, and ready for use.
       */
      public static final int STATE_ON = 12;
      /**
       * Indicates the local Bluetooth adapter is turning off. Local clients
       * should immediately attempt graceful disconnection of any remote links.
       */
      public static final int STATE_TURNING_OFF = 13;
  
      /**
       * Indicates the local Bluetooth adapter is turning Bluetooth LE mode on.
       *
       * @hide
       */
      public static final int STATE_BLE_TURNING_ON = 14;
  
      /**
       * Indicates the local Bluetooth adapter is in LE only mode.
       *
       * @hide
       */
      public static final int STATE_BLE_ON = 15;
  
      /**
       * Indicates the local Bluetooth adapter is turning off LE only mode.
       *
       * @hide
       */
      public static final int STATE_BLE_TURNING_OFF = 16;
  
      /**
       * UUID of the GATT Read Characteristics for LE_PSM value.
       *
       * @hide
       */
      public static final UUID LE_PSM_CHARACTERISTIC_UUID =
              UUID.fromString("2d410339-82b6-42aa-b34e-e2e01df8cc1a");
  
      /**
       * Human-readable string helper for AdapterState
       *
       * @hide
       */
      public static String nameForState(@AdapterState int state) {
          switch (state) {
              case STATE_OFF:
                  return "OFF";
              case STATE_TURNING_ON:
                  return "TURNING_ON";
              case STATE_ON:
                  return "ON";
              case STATE_TURNING_OFF:
                  return "TURNING_OFF";
              case STATE_BLE_TURNING_ON:
                  return "BLE_TURNING_ON";
              case STATE_BLE_ON:
                  return "BLE_ON";
              case STATE_BLE_TURNING_OFF:
                  return "BLE_TURNING_OFF";
              default:
                  return "?!?!? (" + state + ")";
          }
      }
  
      /**
       * Activity Action: Show a system activity that requests discoverable mode.
       * This activity will also request the user to turn on Bluetooth if it
       * is not currently enabled.
       * <p>Discoverable mode is equivalent to {@link
       * #SCAN_MODE_CONNECTABLE_DISCOVERABLE}. It allows remote devices to see
       * this Bluetooth adapter when they perform a discovery.
       * <p>For privacy, Android is not discoverable by default.
       * <p>The sender of this Intent can optionally use extra field {@link
       * #EXTRA_DISCOVERABLE_DURATION} to request the duration of
       * discoverability. Currently the default duration is 120 seconds, and
       * maximum duration is capped at 300 seconds for each request.
       * <p>Notification of the result of this activity is posted using the
       * {@link android.app.Activity#onActivityResult} callback. The
       * <code>resultCode</code>
       * will be the duration (in seconds) of discoverability or
       * {@link android.app.Activity#RESULT_CANCELED} if the user rejected
       * discoverability or an error has occurred.
       * <p>Applications can also listen for {@link #ACTION_SCAN_MODE_CHANGED}
       * for global notification whenever the scan mode changes. For example, an
       * application can be notified when the device has ended discoverability.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH}
       */
      @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION) public static final String
              ACTION_REQUEST_DISCOVERABLE = "android.bluetooth.adapter.action.REQUEST_DISCOVERABLE";
  
      /**
       * Used as an optional int extra field in {@link
       * #ACTION_REQUEST_DISCOVERABLE} intents to request a specific duration
       * for discoverability in seconds. The current default is 120 seconds, and
       * requests over 300 seconds will be capped. These values could change.
       */
      public static final String EXTRA_DISCOVERABLE_DURATION =
              "android.bluetooth.adapter.extra.DISCOVERABLE_DURATION";
  
      /**
       * Activity Action: Show a system activity that allows the user to turn on
       * Bluetooth.
       * <p>This system activity will return once Bluetooth has completed turning
       * on, or the user has decided not to turn Bluetooth on.
       * <p>Notification of the result of this activity is posted using the
       * {@link android.app.Activity#onActivityResult} callback. The
       * <code>resultCode</code>
       * will be {@link android.app.Activity#RESULT_OK} if Bluetooth has been
       * turned on or {@link android.app.Activity#RESULT_CANCELED} if the user
       * has rejected the request or an error has occurred.
       * <p>Applications can also listen for {@link #ACTION_STATE_CHANGED}
       * for global notification whenever Bluetooth is turned on or off.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH}
       */
      @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION) public static final String
              ACTION_REQUEST_ENABLE = "android.bluetooth.adapter.action.REQUEST_ENABLE";
  
      /**
       * Activity Action: Show a system activity that allows the user to turn off
       * Bluetooth. This is used only if permission review is enabled which is for
       * apps targeting API less than 23 require a permission review before any of
       * the app's components can run.
       * <p>This system activity will return once Bluetooth has completed turning
       * off, or the user has decided not to turn Bluetooth off.
       * <p>Notification of the result of this activity is posted using the
       * {@link android.app.Activity#onActivityResult} callback. The
       * <code>resultCode</code>
       * will be {@link android.app.Activity#RESULT_OK} if Bluetooth has been
       * turned off or {@link android.app.Activity#RESULT_CANCELED} if the user
       * has rejected the request or an error has occurred.
       * <p>Applications can also listen for {@link #ACTION_STATE_CHANGED}
       * for global notification whenever Bluetooth is turned on or off.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH}
       *
       * @hide
       */
      @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION) public static final String
              ACTION_REQUEST_DISABLE = "android.bluetooth.adapter.action.REQUEST_DISABLE";
  
      /**
       * Activity Action: Show a system activity that allows user to enable BLE scans even when
       * Bluetooth is turned off.<p>
       *
       * Notification of result of this activity is posted using
       * {@link android.app.Activity#onActivityResult}. The <code>resultCode</code> will be
       * {@link android.app.Activity#RESULT_OK} if BLE scan always available setting is turned on or
       * {@link android.app.Activity#RESULT_CANCELED} if the user has rejected the request or an
       * error occurred.
       *
       * @hide
       */
      @SystemApi
      @SdkConstant(SdkConstantType.ACTIVITY_INTENT_ACTION)
      public static final String ACTION_REQUEST_BLE_SCAN_ALWAYS_AVAILABLE =
              "android.bluetooth.adapter.action.REQUEST_BLE_SCAN_ALWAYS_AVAILABLE";
  
      /**
       * Broadcast Action: Indicates the Bluetooth scan mode of the local Adapter
       * has changed.
       * <p>Always contains the extra fields {@link #EXTRA_SCAN_MODE} and {@link
       * #EXTRA_PREVIOUS_SCAN_MODE} containing the new and old scan modes
       * respectively.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH}
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION) public static final String
              ACTION_SCAN_MODE_CHANGED = "android.bluetooth.adapter.action.SCAN_MODE_CHANGED";
  
      /**
       * Used as an int extra field in {@link #ACTION_SCAN_MODE_CHANGED}
       * intents to request the current scan mode. Possible values are:
       * {@link #SCAN_MODE_NONE},
       * {@link #SCAN_MODE_CONNECTABLE},
       * {@link #SCAN_MODE_CONNECTABLE_DISCOVERABLE},
       */
      public static final String EXTRA_SCAN_MODE = "android.bluetooth.adapter.extra.SCAN_MODE";
      /**
       * Used as an int extra field in {@link #ACTION_SCAN_MODE_CHANGED}
       * intents to request the previous scan mode. Possible values are:
       * {@link #SCAN_MODE_NONE},
       * {@link #SCAN_MODE_CONNECTABLE},
       * {@link #SCAN_MODE_CONNECTABLE_DISCOVERABLE},
       */
      public static final String EXTRA_PREVIOUS_SCAN_MODE =
              "android.bluetooth.adapter.extra.PREVIOUS_SCAN_MODE";
  
      /** @hide */
      @IntDef(prefix = { "SCAN_" }, value = {
              SCAN_MODE_NONE,
              SCAN_MODE_CONNECTABLE,
              SCAN_MODE_CONNECTABLE_DISCOVERABLE
      })
      @Retention(RetentionPolicy.SOURCE)
      public @interface ScanMode {}
  
      /**
       * Indicates that both inquiry scan and page scan are disabled on the local
       * Bluetooth adapter. Therefore this device is neither discoverable
       * nor connectable from remote Bluetooth devices.
       */
      public static final int SCAN_MODE_NONE = 20;
      /**
       * Indicates that inquiry scan is disabled, but page scan is enabled on the
       * local Bluetooth adapter. Therefore this device is not discoverable from
       * remote Bluetooth devices, but is connectable from remote devices that
       * have previously discovered this device.
       */
      public static final int SCAN_MODE_CONNECTABLE = 21;
      /**
       * Indicates that both inquiry scan and page scan are enabled on the local
       * Bluetooth adapter. Therefore this device is both discoverable and
       * connectable from remote Bluetooth devices.
       */
      public static final int SCAN_MODE_CONNECTABLE_DISCOVERABLE = 23;
  
      /**
       * Device only has a display.
       *
       * @hide
       */
      public static final int IO_CAPABILITY_OUT = 0;
  
      /**
       * Device has a display and the ability to input Yes/No.
       *
       * @hide
       */
      public static final int IO_CAPABILITY_IO = 1;
  
      /**
       * Device only has a keyboard for entry but no display.
       *
       * @hide
       */
      public static final int IO_CAPABILITY_IN = 2;
  
      /**
       * Device has no Input or Output capability.
       *
       * @hide
       */
      public static final int IO_CAPABILITY_NONE = 3;
  
      /**
       * Device has a display and a full keyboard.
       *
       * @hide
       */
      public static final int IO_CAPABILITY_KBDISP = 4;
  
      /**
       * Maximum range value for Input/Output capabilities.
       *
       * <p>This should be updated when adding a new Input/Output capability. Other code
       * like validation depends on this being accurate.
       *
       * @hide
       */
      public static final int IO_CAPABILITY_MAX = 5;
  
      /**
       * The Input/Output capability of the device is unknown.
       *
       * @hide
       */
      public static final int IO_CAPABILITY_UNKNOWN = 255;
  
      /** @hide */
      @IntDef({IO_CAPABILITY_OUT, IO_CAPABILITY_IO, IO_CAPABILITY_IN, IO_CAPABILITY_NONE,
              IO_CAPABILITY_KBDISP})
      @Retention(RetentionPolicy.SOURCE)
      public @interface IoCapability {}
  
      /**
       * Broadcast Action: The local Bluetooth adapter has started the remote
       * device discovery process.
       * <p>This usually involves an inquiry scan of about 12 seconds, followed
       * by a page scan of each new device to retrieve its Bluetooth name.
       * <p>Register for {@link BluetoothDevice#ACTION_FOUND} to be notified as
       * remote Bluetooth devices are found.
       * <p>Device discovery is a heavyweight procedure. New connections to
       * remote Bluetooth devices should not be attempted while discovery is in
       * progress, and existing connections will experience limited bandwidth
       * and high latency. Use {@link #cancelDiscovery()} to cancel an ongoing
       * discovery.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH} to receive.
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION) public static final String
              ACTION_DISCOVERY_STARTED = "android.bluetooth.adapter.action.DISCOVERY_STARTED";
      /**
       * Broadcast Action: The local Bluetooth adapter has finished the device
       * discovery process.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH} to receive.
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION) public static final String
              ACTION_DISCOVERY_FINISHED = "android.bluetooth.adapter.action.DISCOVERY_FINISHED";
  
      /**
       * Broadcast Action: The local Bluetooth adapter has changed its friendly
       * Bluetooth name.
       * <p>This name is visible to remote Bluetooth devices.
       * <p>Always contains the extra field {@link #EXTRA_LOCAL_NAME} containing
       * the name.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH} to receive.
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION) public static final String
              ACTION_LOCAL_NAME_CHANGED = "android.bluetooth.adapter.action.LOCAL_NAME_CHANGED";
      /**
       * Used as a String extra field in {@link #ACTION_LOCAL_NAME_CHANGED}
       * intents to request the local Bluetooth name.
       */
      public static final String EXTRA_LOCAL_NAME = "android.bluetooth.adapter.extra.LOCAL_NAME";
  
      /**
       * Intent used to broadcast the change in connection state of the local
       * Bluetooth adapter to a profile of the remote device. When the adapter is
       * not connected to any profiles of any remote devices and it attempts a
       * connection to a profile this intent will be sent. Once connected, this intent
       * will not be sent for any more connection attempts to any profiles of any
       * remote device. When the adapter disconnects from the last profile its
       * connected to of any remote device, this intent will be sent.
       *
       * <p> This intent is useful for applications that are only concerned about
       * whether the local adapter is connected to any profile of any device and
       * are not really concerned about which profile. For example, an application
       * which displays an icon to display whether Bluetooth is connected or not
       * can use this intent.
       *
       * <p>This intent will have 3 extras:
       * {@link #EXTRA_CONNECTION_STATE} - The current connection state.
       * {@link #EXTRA_PREVIOUS_CONNECTION_STATE}- The previous connection state.
       * {@link BluetoothDevice#EXTRA_DEVICE} - The remote device.
       *
       * {@link #EXTRA_CONNECTION_STATE} or {@link #EXTRA_PREVIOUS_CONNECTION_STATE}
       * can be any of {@link #STATE_DISCONNECTED}, {@link #STATE_CONNECTING},
       * {@link #STATE_CONNECTED}, {@link #STATE_DISCONNECTING}.
       *
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH} to receive.
       */
      @SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION) public static final String
              ACTION_CONNECTION_STATE_CHANGED =
              "android.bluetooth.adapter.action.CONNECTION_STATE_CHANGED";
  
      /**
       * Extra used by {@link #ACTION_CONNECTION_STATE_CHANGED}
       *
       * This extra represents the current connection state.
       */
      public static final String EXTRA_CONNECTION_STATE =
              "android.bluetooth.adapter.extra.CONNECTION_STATE";
  
      /**
       * Extra used by {@link #ACTION_CONNECTION_STATE_CHANGED}
       *
       * This extra represents the previous connection state.
       */
      public static final String EXTRA_PREVIOUS_CONNECTION_STATE =
              "android.bluetooth.adapter.extra.PREVIOUS_CONNECTION_STATE";
  
      /**
       * Broadcast Action: The Bluetooth adapter state has changed in LE only mode.
       *
       * @hide
       */
      @SystemApi public static final String ACTION_BLE_STATE_CHANGED =
              "android.bluetooth.adapter.action.BLE_STATE_CHANGED";
  
      /**
       * Intent used to broadcast the change in the Bluetooth address
       * of the local Bluetooth adapter.
       * <p>Always contains the extra field {@link
       * #EXTRA_BLUETOOTH_ADDRESS} containing the Bluetooth address.
       *
       * Note: only system level processes are allowed to send this
       * defined broadcast.
       *
       * @hide
       */
      public static final String ACTION_BLUETOOTH_ADDRESS_CHANGED =
              "android.bluetooth.adapter.action.BLUETOOTH_ADDRESS_CHANGED";
  
      /**
       * Used as a String extra field in {@link
       * #ACTION_BLUETOOTH_ADDRESS_CHANGED} intent to store the local
       * Bluetooth address.
       *
       * @hide
       */
      public static final String EXTRA_BLUETOOTH_ADDRESS =
              "android.bluetooth.adapter.extra.BLUETOOTH_ADDRESS";
  
      /**
       * Broadcast Action: The notifys Bluetooth ACL connected event. This will be
       * by BLE Always on enabled application to know the ACL_CONNECTED event
       * when Bluetooth state in STATE_BLE_ON. This denotes GATT connection
       * as Bluetooth LE is the only feature available in STATE_BLE_ON
       *
       * This is counterpart of {@link BluetoothDevice#ACTION_ACL_CONNECTED} which
       * works in Bluetooth state STATE_ON
       *
       * @hide
       */
      public static final String ACTION_BLE_ACL_CONNECTED =
              "android.bluetooth.adapter.action.BLE_ACL_CONNECTED";
  
      /**
       * Broadcast Action: The notifys Bluetooth ACL connected event. This will be
       * by BLE Always on enabled application to know the ACL_DISCONNECTED event
       * when Bluetooth state in STATE_BLE_ON. This denotes GATT disconnection as Bluetooth
       * LE is the only feature available in STATE_BLE_ON
       *
       * This is counterpart of {@link BluetoothDevice#ACTION_ACL_DISCONNECTED} which
       * works in Bluetooth state STATE_ON
       *
       * @hide
       */
      public static final String ACTION_BLE_ACL_DISCONNECTED =
              "android.bluetooth.adapter.action.BLE_ACL_DISCONNECTED";
  
      /** The profile is in disconnected state */
      public static final int STATE_DISCONNECTED = BluetoothProtoEnums.CONNECTION_STATE_DISCONNECTED;
      /** The profile is in connecting state */
      public static final int STATE_CONNECTING = BluetoothProtoEnums.CONNECTION_STATE_CONNECTING;
      /** The profile is in connected state */
      public static final int STATE_CONNECTED = BluetoothProtoEnums.CONNECTION_STATE_CONNECTED;
      /** The profile is in disconnecting state */
      public static final int STATE_DISCONNECTING =
              BluetoothProtoEnums.CONNECTION_STATE_DISCONNECTING;
  
      /** @hide */
      public static final String BLUETOOTH_MANAGER_SERVICE = "bluetooth_manager";
      private final IBinder mToken;
  
  
      /**
       * When creating a ServerSocket using listenUsingRfcommOn() or
       * listenUsingL2capOn() use SOCKET_CHANNEL_AUTO_STATIC to create
       * a ServerSocket that auto assigns a channel number to the first
       * bluetooth socket.
       * The channel number assigned to this first Bluetooth Socket will
       * be stored in the ServerSocket, and reused for subsequent Bluetooth
       * sockets.
       *
       * @hide
       */
      public static final int SOCKET_CHANNEL_AUTO_STATIC_NO_SDP = -2;
  
  
      private static final int ADDRESS_LENGTH = 17;
  
      /**
       * Lazily initialized singleton. Guaranteed final after first object
       * constructed.
       */
      private static BluetoothAdapter sAdapter;
  
      private static BluetoothLeScanner sBluetoothLeScanner;
      private static BluetoothLeAdvertiser sBluetoothLeAdvertiser;
      private static PeriodicAdvertisingManager sPeriodicAdvertisingManager;
  
      private final IBluetoothManager mManagerService;
      @UnsupportedAppUsage
      private IBluetooth mService;
      private Context mContext;
      private final ReentrantReadWriteLock mServiceLock = new ReentrantReadWriteLock();
  
      private final Object mLock = new Object();
      private final Map<LeScanCallback, ScanCallback> mLeScanClients;
      private static final Map<BluetoothDevice, List<Pair<OnMetadataChangedListener, Executor>>>
                  sMetadataListeners = new HashMap<>();
  
      /**
       * Bluetooth metadata listener. Overrides the default BluetoothMetadataListener
       * implementation.
       */
      private static final IBluetoothMetadataListener sBluetoothMetadataListener =
              new IBluetoothMetadataListener.Stub() {
          @Override
          public void onMetadataChanged(BluetoothDevice device, int key, byte[] value) {
              synchronized (sMetadataListeners) {
                  if (sMetadataListeners.containsKey(device)) {
                      List<Pair<OnMetadataChangedListener, Executor>> list =
                              sMetadataListeners.get(device);
                      for (Pair<OnMetadataChangedListener, Executor> pair : list) {
                          OnMetadataChangedListener listener = pair.first;
                          Executor executor = pair.second;
                          executor.execute(() -> {
                              listener.onMetadataChanged(device, key, value);
                          });
                      }
                  }
              }
              return;
          }
      };
  
      /**
       * Get a handle to the default local Bluetooth adapter.
       * <p>Currently Android only supports one Bluetooth adapter, but the API
       * could be extended to support more. This will always return the default
       * adapter.
       * </p>
       *
       * @return the default local adapter, or null if Bluetooth is not supported on this hardware
       * platform
       */
      public static synchronized BluetoothAdapter getDefaultAdapter() {
          if (sAdapter == null) {
              IBinder b = ServiceManager.getService(BLUETOOTH_MANAGER_SERVICE);
              if (b != null) {
                  IBluetoothManager managerService = IBluetoothManager.Stub.asInterface(b);
                  sAdapter = new BluetoothAdapter(managerService);
              } else {
                  Log.e(TAG, "Bluetooth binder is null");
              }
          }
          return sAdapter;
      }
  
      /**
       * Use {@link #getDefaultAdapter} to get the BluetoothAdapter instance.
       */
      BluetoothAdapter(IBluetoothManager managerService) {
  
          if (managerService == null) {
              throw new IllegalArgumentException("bluetooth manager service is null");
          }
          try {
              mServiceLock.writeLock().lock();
              mService = managerService.registerAdapter(mManagerCallback);
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.writeLock().unlock();
          }
          mManagerService = managerService;
          mLeScanClients = new HashMap<LeScanCallback, ScanCallback>();
          mToken = new Binder();
      }
  
      /**
       * Get a {@link BluetoothDevice} object for the given Bluetooth hardware
       * address.
       * <p>Valid Bluetooth hardware addresses must be upper case, in a format
       * such as "00:11:22:33:AA:BB". The helper {@link #checkBluetoothAddress} is
       * available to validate a Bluetooth address.
       * <p>A {@link BluetoothDevice} will always be returned for a valid
       * hardware address, even if this adapter has never seen that device.
       *
       * @param address valid Bluetooth MAC address
       * @throws IllegalArgumentException if address is invalid
       */
      public BluetoothDevice getRemoteDevice(String address) {
          return new BluetoothDevice(address);
      }
  
      /**
       * Get a {@link BluetoothDevice} object for the given Bluetooth hardware
       * address.
       * <p>Valid Bluetooth hardware addresses must be 6 bytes. This method
       * expects the address in network byte order (MSB first).
       * <p>A {@link BluetoothDevice} will always be returned for a valid
       * hardware address, even if this adapter has never seen that device.
       *
       * @param address Bluetooth MAC address (6 bytes)
       * @throws IllegalArgumentException if address is invalid
       */
      public BluetoothDevice getRemoteDevice(byte[] address) {
          if (address == null || address.length != 6) {
              throw new IllegalArgumentException("Bluetooth address must have 6 bytes");
          }
          return new BluetoothDevice(
                  String.format(Locale.US, "%02X:%02X:%02X:%02X:%02X:%02X", address[0], address[1],
                          address[2], address[3], address[4], address[5]));
      }
  
      /**
       * Returns a {@link BluetoothLeAdvertiser} object for Bluetooth LE Advertising operations.
       * Will return null if Bluetooth is turned off or if Bluetooth LE Advertising is not
       * supported on this device.
       * <p>
       * Use {@link #isMultipleAdvertisementSupported()} to check whether LE Advertising is supported
       * on this device before calling this method.
       */
      public BluetoothLeAdvertiser getBluetoothLeAdvertiser() {
          if (!getLeAccess()) {
              return null;
          }
          synchronized (mLock) {
              if (sBluetoothLeAdvertiser == null) {
                  sBluetoothLeAdvertiser = new BluetoothLeAdvertiser(mManagerService);
              }
          }
          return sBluetoothLeAdvertiser;
      }
  
      /**
       * Returns a {@link PeriodicAdvertisingManager} object for Bluetooth LE Periodic Advertising
       * operations. Will return null if Bluetooth is turned off or if Bluetooth LE Periodic
       * Advertising is not supported on this device.
       * <p>
       * Use {@link #isLePeriodicAdvertisingSupported()} to check whether LE Periodic Advertising is
       * supported on this device before calling this method.
       *
       * @hide
       */
      public PeriodicAdvertisingManager getPeriodicAdvertisingManager() {
          if (!getLeAccess()) {
              return null;
          }
  
          if (!isLePeriodicAdvertisingSupported()) {
              return null;
          }
  
          synchronized (mLock) {
              if (sPeriodicAdvertisingManager == null) {
                  sPeriodicAdvertisingManager = new PeriodicAdvertisingManager(mManagerService);
              }
          }
          return sPeriodicAdvertisingManager;
      }
  
      /**
       * Returns a {@link BluetoothLeScanner} object for Bluetooth LE scan operations.
       */
      public BluetoothLeScanner getBluetoothLeScanner() {
          if (!getLeAccess()) {
              return null;
          }
          synchronized (mLock) {
              if (sBluetoothLeScanner == null) {
                  sBluetoothLeScanner = new BluetoothLeScanner(mManagerService);
              }
          }
          return sBluetoothLeScanner;
      }
  
      /**
       * Return true if Bluetooth is currently enabled and ready for use.
       * <p>Equivalent to:
       * <code>getBluetoothState() == STATE_ON</code>
       *
       * @return true if the local adapter is turned on
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public boolean isEnabled() {
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.isEnabled();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
  
          return false;
      }
  
      /**
       * Return true if Bluetooth LE(Always BLE On feature) is currently
       * enabled and ready for use
       * <p>This returns true if current state is either STATE_ON or STATE_BLE_ON
       *
       * @return true if the local Bluetooth LE adapter is turned on
       * @hide
       */
      @SystemApi
      public boolean isLeEnabled() {
          final int state = getLeState();
          if (DBG) {
              Log.d(TAG, "isLeEnabled(): " + BluetoothAdapter.nameForState(state));
          }
          return (state == BluetoothAdapter.STATE_ON || state == BluetoothAdapter.STATE_BLE_ON);
      }
  
      /**
       * Turns off Bluetooth LE which was earlier turned on by calling enableBLE().
       *
       * <p> If the internal Adapter state is STATE_BLE_ON, this would trigger the transition
       * to STATE_OFF and completely shut-down Bluetooth
       *
       * <p> If the Adapter state is STATE_ON, This would unregister the existance of
       * special Bluetooth LE application and hence the further turning off of Bluetooth
       * from UI would ensure the complete turn-off of Bluetooth rather than staying back
       * BLE only state
       *
       * <p>This is an asynchronous call: it will return immediately, and
       * clients should listen for {@link #ACTION_BLE_STATE_CHANGED}
       * to be notified of subsequent adapter state changes If this call returns
       * true, then the adapter state will immediately transition from {@link
       * #STATE_ON} to {@link #STATE_TURNING_OFF}, and some time
       * later transition to either {@link #STATE_BLE_ON} or {@link
       * #STATE_OFF} based on the existance of the further Always BLE ON enabled applications
       * If this call returns false then there was an
       * immediate problem that will prevent the QAdapter from being turned off -
       * such as the QAadapter already being turned off.
       *
       * @return true to indicate success, or false on immediate error
       * @hide
       */
      @SystemApi
      public boolean disableBLE() {
          if (!isBleScanAlwaysAvailable()) {
              return false;
          }
  
          int state = getLeState();
          if (state == BluetoothAdapter.STATE_ON || state == BluetoothAdapter.STATE_BLE_ON) {
              String packageName = ActivityThread.currentPackageName();
              if (DBG) {
                  Log.d(TAG, "disableBLE(): de-registering " + packageName);
              }
              try {
                  mManagerService.updateBleAppCount(mToken, false, packageName);
              } catch (RemoteException e) {
                  Log.e(TAG, "", e);
              }
              return true;
          }
  
          if (DBG) {
              Log.d(TAG, "disableBLE(): Already disabled");
          }
          return false;
      }
  
      /**
       * Applications who want to only use Bluetooth Low Energy (BLE) can call enableBLE.
       *
       * enableBLE registers the existence of an app using only LE functions.
       *
       * enableBLE may enable Bluetooth to an LE only mode so that an app can use
       * LE related features (BluetoothGatt or BluetoothGattServer classes)
       *
       * If the user disables Bluetooth while an app is registered to use LE only features,
       * Bluetooth will remain on in LE only mode for the app.
       *
       * When Bluetooth is in LE only mode, it is not shown as ON to the UI.
       *
       * <p>This is an asynchronous call: it returns immediately, and
       * clients should listen for {@link #ACTION_BLE_STATE_CHANGED}
       * to be notified of adapter state changes.
       *
       * If this call returns * true, then the adapter state is either in a mode where
       * LE is available, or will transition from {@link #STATE_OFF} to {@link #STATE_BLE_TURNING_ON},
       * and some time later transition to either {@link #STATE_OFF} or {@link #STATE_BLE_ON}.
       *
       * If this call returns false then there was an immediate problem that prevents the
       * adapter from being turned on - such as Airplane mode.
       *
       * {@link #ACTION_BLE_STATE_CHANGED} returns the Bluetooth Adapter's various
       * states, It includes all the classic Bluetooth Adapter states along with
       * internal BLE only states
       *
       * @return true to indicate Bluetooth LE will be available, or false on immediate error
       * @hide
       */
      @SystemApi
      public boolean enableBLE() {
          if (!isBleScanAlwaysAvailable()) {
              return false;
          }
  
          try {
              String packageName = ActivityThread.currentPackageName();
              mManagerService.updateBleAppCount(mToken, true, packageName);
              if (isLeEnabled()) {
                  if (DBG) {
                      Log.d(TAG, "enableBLE(): Bluetooth already enabled");
                  }
                  return true;
              }
              if (DBG) {
                  Log.d(TAG, "enableBLE(): Calling enable");
              }
              return mManagerService.enable(packageName);
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          }
  
          return false;
      }
  
      /**
       * Get the current state of the local Bluetooth adapter.
       * <p>Possible return values are
       * {@link #STATE_OFF},
       * {@link #STATE_TURNING_ON},
       * {@link #STATE_ON},
       * {@link #STATE_TURNING_OFF}.
       *
       * @return current state of Bluetooth adapter
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      @AdapterState
      public int getState() {
          int state = BluetoothAdapter.STATE_OFF;
  
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  state = mService.getState();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
  
          // Consider all internal states as OFF
          if (state == BluetoothAdapter.STATE_BLE_ON || state == BluetoothAdapter.STATE_BLE_TURNING_ON
                  || state == BluetoothAdapter.STATE_BLE_TURNING_OFF) {
              if (VDBG) {
                  Log.d(TAG, "Consider " + BluetoothAdapter.nameForState(state) + " state as OFF");
              }
              state = BluetoothAdapter.STATE_OFF;
          }
          if (VDBG) {
              Log.d(TAG, "" + hashCode() + ": getState(). Returning " + BluetoothAdapter.nameForState(
                      state));
          }
          return state;
      }
  
      /**
       * Get the current state of the local Bluetooth adapter
       * <p>This returns current internal state of Adapter including LE ON/OFF
       *
       * <p>Possible return values are
       * {@link #STATE_OFF},
       * {@link #STATE_BLE_TURNING_ON},
       * {@link #STATE_BLE_ON},
       * {@link #STATE_TURNING_ON},
       * {@link #STATE_ON},
       * {@link #STATE_TURNING_OFF},
       * {@link #STATE_BLE_TURNING_OFF}.
       *
       * @return current state of Bluetooth adapter
       * @hide
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      @AdapterState
      @UnsupportedAppUsage
      public int getLeState() {
          int state = BluetoothAdapter.STATE_OFF;
  
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  state = mService.getState();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
  
          if (VDBG) {
              Log.d(TAG, "getLeState() returning " + BluetoothAdapter.nameForState(state));
          }
          return state;
      }
  
      boolean getLeAccess() {
          if (getLeState() == STATE_ON) {
              return true;
          } else if (getLeState() == STATE_BLE_ON) {
              return true; // TODO: FILTER SYSTEM APPS HERE <--
          }
  
          return false;
      }
  
      /**
       * Turn on the local Bluetooth adapter&mdash;do not use without explicit
       * user action to turn on Bluetooth.
       * <p>This powers on the underlying Bluetooth hardware, and starts all
       * Bluetooth system services.
       * <p class="caution"><strong>Bluetooth should never be enabled without
       * direct user consent</strong>. If you want to turn on Bluetooth in order
       * to create a wireless connection, you should use the {@link
       * #ACTION_REQUEST_ENABLE} Intent, which will raise a dialog that requests
       * user permission to turn on Bluetooth. The {@link #enable()} method is
       * provided only for applications that include a user interface for changing
       * system settings, such as a "power manager" app.</p>
       * <p>This is an asynchronous call: it will return immediately, and
       * clients should listen for {@link #ACTION_STATE_CHANGED}
       * to be notified of subsequent adapter state changes. If this call returns
       * true, then the adapter state will immediately transition from {@link
       * #STATE_OFF} to {@link #STATE_TURNING_ON}, and some time
       * later transition to either {@link #STATE_OFF} or {@link
       * #STATE_ON}. If this call returns false then there was an
       * immediate problem that will prevent the adapter from being turned on -
       * such as Airplane mode, or the adapter is already turned on.
       *
       * @return true to indicate adapter startup has begun, or false on immediate error
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      public boolean enable() {
          if (isEnabled()) {
              if (DBG) {
                  Log.d(TAG, "enable(): BT already enabled!");
              }
              return true;
          }
          try {
              return mManagerService.enable(ActivityThread.currentPackageName());
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          }
          return false;
      }
  
      /**
       * Turn off the local Bluetooth adapter&mdash;do not use without explicit
       * user action to turn off Bluetooth.
       * <p>This gracefully shuts down all Bluetooth connections, stops Bluetooth
       * system services, and powers down the underlying Bluetooth hardware.
       * <p class="caution"><strong>Bluetooth should never be disabled without
       * direct user consent</strong>. The {@link #disable()} method is
       * provided only for applications that include a user interface for changing
       * system settings, such as a "power manager" app.</p>
       * <p>This is an asynchronous call: it will return immediately, and
       * clients should listen for {@link #ACTION_STATE_CHANGED}
       * to be notified of subsequent adapter state changes. If this call returns
       * true, then the adapter state will immediately transition from {@link
       * #STATE_ON} to {@link #STATE_TURNING_OFF}, and some time
       * later transition to either {@link #STATE_OFF} or {@link
       * #STATE_ON}. If this call returns false then there was an
       * immediate problem that will prevent the adapter from being turned off -
       * such as the adapter already being turned off.
       *
       * @return true to indicate adapter shutdown has begun, or false on immediate error
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      public boolean disable() {
          try {
              return mManagerService.disable(ActivityThread.currentPackageName(), true);
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          }
          return false;
      }
  
      /**
       * Turn off the local Bluetooth adapter and don't persist the setting.
       *
       * <p>Requires the {@link android.Manifest.permission#BLUETOOTH_ADMIN}
       * permission
       *
       * @return true to indicate adapter shutdown has begun, or false on immediate error
       * @hide
       */
      @UnsupportedAppUsage
      public boolean disable(boolean persist) {
  
          try {
              return mManagerService.disable(ActivityThread.currentPackageName(), persist);
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          }
          return false;
      }
  
      /**
       * Returns the hardware address of the local Bluetooth adapter.
       * <p>For example, "00:11:22:AA:BB:CC".
       *
       * @return Bluetooth hardware address as string
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public String getAddress() {
          try {
              return mManagerService.getAddress();
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          }
          return null;
      }
  
      /**
       * Get the friendly Bluetooth name of the local Bluetooth adapter.
       * <p>This name is visible to remote Bluetooth devices.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH}
       *
       * @return the Bluetooth name, or null on error
       */
      public String getName() {
          try {
              return mManagerService.getName();
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          }
          return null;
      }
  
      /**
       * Factory reset bluetooth settings.
       *
       * <p>Requires the {@link android.Manifest.permission#BLUETOOTH_PRIVILEGED}
       * permission
       *
       * @return true to indicate that the config file was successfully cleared
       * @hide
       */
      @UnsupportedAppUsage
      public boolean factoryReset() {
          try {
              mServiceLock.readLock().lock();
              if (mService != null && mService.factoryReset()
                      && mManagerService != null && mManagerService.onFactoryReset()) {
                  return true;
              }
              Log.e(TAG, "factoryReset(): Setting persist.bluetooth.factoryreset to retry later");
              SystemProperties.set("persist.bluetooth.factoryreset", "true");
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Get the UUIDs supported by the local Bluetooth adapter.
       *
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH}
       *
       * @return the UUIDs supported by the local Bluetooth Adapter.
       * @hide
       */
      @UnsupportedAppUsage
      public ParcelUuid[] getUuids() {
          if (getState() != STATE_ON) {
              return null;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.getUuids();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return null;
      }
  
      /**
       * Set the friendly Bluetooth name of the local Bluetooth adapter.
       * <p>This name is visible to remote Bluetooth devices.
       * <p>Valid Bluetooth names are a maximum of 248 bytes using UTF-8
       * encoding, although many remote devices can only display the first
       * 40 characters, and some may be limited to just 20.
       * <p>If Bluetooth state is not {@link #STATE_ON}, this API
       * will return false. After turning on Bluetooth,
       * wait for {@link #ACTION_STATE_CHANGED} with {@link #STATE_ON}
       * to get the updated value.
       *
       * @param name a valid Bluetooth name
       * @return true if the name was set, false otherwise
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      public boolean setName(String name) {
          if (getState() != STATE_ON) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.setName(name);
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Returns the {@link BluetoothClass} Bluetooth Class of Device (CoD) of the local Bluetooth
       * adapter.
       *
       * @return {@link BluetoothClass} Bluetooth CoD of local Bluetooth device.
       *
       * @hide
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      public BluetoothClass getBluetoothClass() {
          if (getState() != STATE_ON) {
              return null;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.getBluetoothClass();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return null;
      }
  
      /**
       * Sets the {@link BluetoothClass} Bluetooth Class of Device (CoD) of the local Bluetooth
       * adapter.
       *
       * <p>Note: This value persists across system reboot.
       *
       * @param bluetoothClass {@link BluetoothClass} to set the local Bluetooth adapter to.
       * @return true if successful, false if unsuccessful.
       *
       * @hide
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
      public boolean setBluetoothClass(BluetoothClass bluetoothClass) {
          if (getState() != STATE_ON) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.setBluetoothClass(bluetoothClass);
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Returns the Input/Output capability of the device for classic Bluetooth.
       *
       * @return Input/Output capability of the device. One of {@link #IO_CAPABILITY_OUT},
       *         {@link #IO_CAPABILITY_IO}, {@link #IO_CAPABILITY_IN}, {@link #IO_CAPABILITY_NONE},
       *         {@link #IO_CAPABILITY_KBDISP} or {@link #IO_CAPABILITY_UNKNOWN}.
       *
       * @hide
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      @IoCapability
      public int getIoCapability() {
          if (getState() != STATE_ON) return BluetoothAdapter.IO_CAPABILITY_UNKNOWN;
          try {
              mServiceLock.readLock().lock();
              if (mService != null) return mService.getIoCapability();
          } catch (RemoteException e) {
              Log.e(TAG, e.getMessage(), e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return BluetoothAdapter.IO_CAPABILITY_UNKNOWN;
      }
  
      /**
       * Sets the Input/Output capability of the device for classic Bluetooth.
       *
       * <p>Changing the Input/Output capability of a device only takes effect on restarting the
       * Bluetooth stack. You would need to restart the stack using {@link BluetoothAdapter#disable()}
       * and {@link BluetoothAdapter#enable()} to see the changes.
       *
       * @param capability Input/Output capability of the device. One of {@link #IO_CAPABILITY_OUT},
       *                   {@link #IO_CAPABILITY_IO}, {@link #IO_CAPABILITY_IN},
       *                   {@link #IO_CAPABILITY_NONE} or {@link #IO_CAPABILITY_KBDISP}.
       *
       * @hide
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
      public boolean setIoCapability(@IoCapability int capability) {
          if (getState() != STATE_ON) return false;
          try {
              mServiceLock.readLock().lock();
              if (mService != null) return mService.setIoCapability(capability);
          } catch (RemoteException e) {
              Log.e(TAG, e.getMessage(), e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Returns the Input/Output capability of the device for BLE operations.
       *
       * @return Input/Output capability of the device. One of {@link #IO_CAPABILITY_OUT},
       *         {@link #IO_CAPABILITY_IO}, {@link #IO_CAPABILITY_IN}, {@link #IO_CAPABILITY_NONE},
       *         {@link #IO_CAPABILITY_KBDISP} or {@link #IO_CAPABILITY_UNKNOWN}.
       *
       * @hide
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      @IoCapability
      public int getLeIoCapability() {
          if (getState() != STATE_ON) return BluetoothAdapter.IO_CAPABILITY_UNKNOWN;
          try {
              mServiceLock.readLock().lock();
              if (mService != null) return mService.getLeIoCapability();
          } catch (RemoteException e) {
              Log.e(TAG, e.getMessage(), e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return BluetoothAdapter.IO_CAPABILITY_UNKNOWN;
      }
  
      /**
       * Sets the Input/Output capability of the device for BLE operations.
       *
       * <p>Changing the Input/Output capability of a device only takes effect on restarting the
       * Bluetooth stack. You would need to restart the stack using {@link BluetoothAdapter#disable()}
       * and {@link BluetoothAdapter#enable()} to see the changes.
       *
       * @param capability Input/Output capability of the device. One of {@link #IO_CAPABILITY_OUT},
       *                   {@link #IO_CAPABILITY_IO}, {@link #IO_CAPABILITY_IN},
       *                   {@link #IO_CAPABILITY_NONE} or {@link #IO_CAPABILITY_KBDISP}.
       *
       * @hide
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
      public boolean setLeIoCapability(@IoCapability int capability) {
          if (getState() != STATE_ON) return false;
          try {
              mServiceLock.readLock().lock();
              if (mService != null) return mService.setLeIoCapability(capability);
          } catch (RemoteException e) {
              Log.e(TAG, e.getMessage(), e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Get the current Bluetooth scan mode of the local Bluetooth adapter.
       * <p>The Bluetooth scan mode determines if the local adapter is
       * connectable and/or discoverable from remote Bluetooth devices.
       * <p>Possible values are:
       * {@link #SCAN_MODE_NONE},
       * {@link #SCAN_MODE_CONNECTABLE},
       * {@link #SCAN_MODE_CONNECTABLE_DISCOVERABLE}.
       * <p>If Bluetooth state is not {@link #STATE_ON}, this API
       * will return {@link #SCAN_MODE_NONE}. After turning on Bluetooth,
       * wait for {@link #ACTION_STATE_CHANGED} with {@link #STATE_ON}
       * to get the updated value.
       *
       * @return scan mode
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      @ScanMode
      public int getScanMode() {
          if (getState() != STATE_ON) {
              return SCAN_MODE_NONE;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.getScanMode();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return SCAN_MODE_NONE;
      }
  
      /**
       * Set the Bluetooth scan mode of the local Bluetooth adapter.
       * <p>The Bluetooth scan mode determines if the local adapter is
       * connectable and/or discoverable from remote Bluetooth devices.
       * <p>For privacy reasons, discoverable mode is automatically turned off
       * after <code>duration</code> seconds. For example, 120 seconds should be
       * enough for a remote device to initiate and complete its discovery
       * process.
       * <p>Valid scan mode values are:
       * {@link #SCAN_MODE_NONE},
       * {@link #SCAN_MODE_CONNECTABLE},
       * {@link #SCAN_MODE_CONNECTABLE_DISCOVERABLE}.
       * <p>If Bluetooth state is not {@link #STATE_ON}, this API
       * will return false. After turning on Bluetooth,
       * wait for {@link #ACTION_STATE_CHANGED} with {@link #STATE_ON}
       * to get the updated value.
       * <p>Requires {@link android.Manifest.permission#WRITE_SECURE_SETTINGS}
       * <p>Applications cannot set the scan mode. They should use
       * <code>startActivityForResult(
       * BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE})
       * </code>instead.
       *
       * @param mode valid scan mode
       * @param duration time in seconds to apply scan mode, only used for {@link
       * #SCAN_MODE_CONNECTABLE_DISCOVERABLE}
       * @return true if the scan mode was set, false otherwise
       * @hide
       */
      @UnsupportedAppUsage
      public boolean setScanMode(@ScanMode int mode, int duration) {
          if (getState() != STATE_ON) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.setScanMode(mode, duration);
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /** @hide */
      @UnsupportedAppUsage
      public boolean setScanMode(int mode) {
          if (getState() != STATE_ON) {
              return false;
          }
          /* getDiscoverableTimeout() to use the latest from NV than use 0 */
          return setScanMode(mode, getDiscoverableTimeout());
      }
  
      /** @hide */
      @UnsupportedAppUsage
      public int getDiscoverableTimeout() {
          if (getState() != STATE_ON) {
              return -1;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.getDiscoverableTimeout();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return -1;
      }
  
      /** @hide */
      @UnsupportedAppUsage
      public void setDiscoverableTimeout(int timeout) {
          if (getState() != STATE_ON) {
              return;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  mService.setDiscoverableTimeout(timeout);
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
      }
  
      /**
       * Get the end time of the latest remote device discovery process.
       *
       * @return the latest time that the bluetooth adapter was/will be in discovery mode, in
       * milliseconds since the epoch. This time can be in the future if {@link #startDiscovery()} has
       * been called recently.
       * @hide
       */
      public long getDiscoveryEndMillis() {
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.getDiscoveryEndMillis();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return -1;
      }
  
      /**
       * Set the context for this BluetoothAdapter (only called from BluetoothManager)
       * @hide
       */
      public void setContext(Context context) {
          mContext = context;
      }
  
      private String getOpPackageName() {
          // Workaround for legacy API for getting a BluetoothAdapter not
          // passing a context
          if (mContext != null) {
              return mContext.getOpPackageName();
          }
          return ActivityThread.currentOpPackageName();
      }
  
      /**
       * Start the remote device discovery process.
       * <p>The discovery process usually involves an inquiry scan of about 12
       * seconds, followed by a page scan of each new device to retrieve its
       * Bluetooth name.
       * <p>This is an asynchronous call, it will return immediately. Register
       * for {@link #ACTION_DISCOVERY_STARTED} and {@link
       * #ACTION_DISCOVERY_FINISHED} intents to determine exactly when the
       * discovery starts and completes. Register for {@link
       * BluetoothDevice#ACTION_FOUND} to be notified as remote Bluetooth devices
       * are found.
       * <p>Device discovery is a heavyweight procedure. New connections to
       * remote Bluetooth devices should not be attempted while discovery is in
       * progress, and existing connections will experience limited bandwidth
       * and high latency. Use {@link #cancelDiscovery()} to cancel an ongoing
       * discovery. Discovery is not managed by the Activity,
       * but is run as a system service, so an application should always call
       * {@link BluetoothAdapter#cancelDiscovery()} even if it
       * did not directly request a discovery, just to be sure.
       * <p>Device discovery will only find remote devices that are currently
       * <i>discoverable</i> (inquiry scan enabled). Many Bluetooth devices are
       * not discoverable by default, and need to be entered into a special mode.
       * <p>If Bluetooth state is not {@link #STATE_ON}, this API
       * will return false. After turning on Bluetooth,
       * wait for {@link #ACTION_STATE_CHANGED} with {@link #STATE_ON}
       * to get the updated value.
       *
       * @return true on success, false on error
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      public boolean startDiscovery() {
          if (getState() != STATE_ON) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.startDiscovery(getOpPackageName());
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Cancel the current device discovery process.
       * <p>Because discovery is a heavyweight procedure for the Bluetooth
       * adapter, this method should always be called before attempting to connect
       * to a remote device with {@link
       * android.bluetooth.BluetoothSocket#connect()}. Discovery is not managed by
       * the  Activity, but is run as a system service, so an application should
       * always call cancel discovery even if it did not directly request a
       * discovery, just to be sure.
       * <p>If Bluetooth state is not {@link #STATE_ON}, this API
       * will return false. After turning on Bluetooth,
       * wait for {@link #ACTION_STATE_CHANGED} with {@link #STATE_ON}
       * to get the updated value.
       *
       * @return true on success, false on error
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      public boolean cancelDiscovery() {
          if (getState() != STATE_ON) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.cancelDiscovery();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Return true if the local Bluetooth adapter is currently in the device
       * discovery process.
       * <p>Device discovery is a heavyweight procedure. New connections to
       * remote Bluetooth devices should not be attempted while discovery is in
       * progress, and existing connections will experience limited bandwidth
       * and high latency. Use {@link #cancelDiscovery()} to cancel an ongoing
       * discovery.
       * <p>Applications can also register for {@link #ACTION_DISCOVERY_STARTED}
       * or {@link #ACTION_DISCOVERY_FINISHED} to be notified when discovery
       * starts or completes.
       * <p>If Bluetooth state is not {@link #STATE_ON}, this API
       * will return false. After turning on Bluetooth,
       * wait for {@link #ACTION_STATE_CHANGED} with {@link #STATE_ON}
       * to get the updated value.
       *
       * @return true if discovering
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public boolean isDiscovering() {
          if (getState() != STATE_ON) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.isDiscovering();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Return true if the multi advertisement is supported by the chipset
       *
       * @return true if Multiple Advertisement feature is supported
       */
      public boolean isMultipleAdvertisementSupported() {
          if (getState() != STATE_ON) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.isMultiAdvertisementSupported();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "failed to get isMultipleAdvertisementSupported, error: ", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Returns {@code true} if BLE scan is always available, {@code false} otherwise. <p>
       *
       * If this returns {@code true}, application can issue {@link BluetoothLeScanner#startScan} and
       * fetch scan results even when Bluetooth is turned off.<p>
       *
       * To change this setting, use {@link #ACTION_REQUEST_BLE_SCAN_ALWAYS_AVAILABLE}.
       *
       * @hide
       */
      @SystemApi
      public boolean isBleScanAlwaysAvailable() {
          try {
              return mManagerService.isBleScanAlwaysAvailable();
          } catch (RemoteException e) {
              Log.e(TAG, "remote expection when calling isBleScanAlwaysAvailable", e);
              return false;
          }
      }
  
      /**
       * Return true if offloaded filters are supported
       *
       * @return true if chipset supports on-chip filtering
       */
      public boolean isOffloadedFilteringSupported() {
          if (!getLeAccess()) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.isOffloadedFilteringSupported();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "failed to get isOffloadedFilteringSupported, error: ", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Return true if offloaded scan batching is supported
       *
       * @return true if chipset supports on-chip scan batching
       */
      public boolean isOffloadedScanBatchingSupported() {
          if (!getLeAccess()) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.isOffloadedScanBatchingSupported();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "failed to get isOffloadedScanBatchingSupported, error: ", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Return true if LE 2M PHY feature is supported.
       *
       * @return true if chipset supports LE 2M PHY feature
       */
      public boolean isLe2MPhySupported() {
          if (!getLeAccess()) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.isLe2MPhySupported();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "failed to get isExtendedAdvertisingSupported, error: ", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Return true if LE Coded PHY feature is supported.
       *
       * @return true if chipset supports LE Coded PHY feature
       */
      public boolean isLeCodedPhySupported() {
          if (!getLeAccess()) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.isLeCodedPhySupported();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "failed to get isLeCodedPhySupported, error: ", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Return true if LE Extended Advertising feature is supported.
       *
       * @return true if chipset supports LE Extended Advertising feature
       */
      public boolean isLeExtendedAdvertisingSupported() {
          if (!getLeAccess()) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.isLeExtendedAdvertisingSupported();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "failed to get isLeExtendedAdvertisingSupported, error: ", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Return true if LE Periodic Advertising feature is supported.
       *
       * @return true if chipset supports LE Periodic Advertising feature
       */
      public boolean isLePeriodicAdvertisingSupported() {
          if (!getLeAccess()) {
              return false;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.isLePeriodicAdvertisingSupported();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "failed to get isLePeriodicAdvertisingSupported, error: ", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return false;
      }
  
      /**
       * Return the maximum LE advertising data length in bytes,
       * if LE Extended Advertising feature is supported, 0 otherwise.
       *
       * @return the maximum LE advertising data length.
       */
      public int getLeMaximumAdvertisingDataLength() {
          if (!getLeAccess()) {
              return 0;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.getLeMaximumAdvertisingDataLength();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "failed to get getLeMaximumAdvertisingDataLength, error: ", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return 0;
      }
  
      /**
       * Return true if Hearing Aid Profile is supported.
       *
       * @return true if phone supports Hearing Aid Profile
       */
      private boolean isHearingAidProfileSupported() {
          try {
              return mManagerService.isHearingAidProfileSupported();
          } catch (RemoteException e) {
              Log.e(TAG, "remote expection when calling isHearingAidProfileSupported", e);
              return false;
          }
      }
  
      /**
       * Get the maximum number of connected audio devices.
       *
       * @return the maximum number of connected audio devices
       * @hide
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public int getMaxConnectedAudioDevices() {
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.getMaxConnectedAudioDevices();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "failed to get getMaxConnectedAudioDevices, error: ", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return 1;
      }
  
      /**
       * Return true if hardware has entries available for matching beacons
       *
       * @return true if there are hw entries available for matching beacons
       * @hide
       */
      public boolean isHardwareTrackingFiltersAvailable() {
          if (!getLeAccess()) {
              return false;
          }
          try {
              IBluetoothGatt iGatt = mManagerService.getBluetoothGatt();
              if (iGatt == null) {
                  // BLE is not supported
                  return false;
              }
              return (iGatt.numHwTrackFiltersAvailable() != 0);
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          }
          return false;
      }
  
      /**
       * Return the record of {@link BluetoothActivityEnergyInfo} object that
       * has the activity and energy info. This can be used to ascertain what
       * the controller has been up to, since the last sample.
       *
       * @param updateType Type of info, cached vs refreshed.
       * @return a record with {@link BluetoothActivityEnergyInfo} or null if report is unavailable or
       * unsupported
       * @hide
       * @deprecated use the asynchronous {@link #requestControllerActivityEnergyInfo(ResultReceiver)}
       * instead.
       */
      @Deprecated
      public BluetoothActivityEnergyInfo getControllerActivityEnergyInfo(int updateType) {
          SynchronousResultReceiver receiver = new SynchronousResultReceiver();
          requestControllerActivityEnergyInfo(receiver);
          try {
              SynchronousResultReceiver.Result result = receiver.awaitResult(1000);
              if (result.bundle != null) {
                  return result.bundle.getParcelable(BatteryStats.RESULT_RECEIVER_CONTROLLER_KEY);
              }
          } catch (TimeoutException e) {
              Log.e(TAG, "getControllerActivityEnergyInfo timed out");
          }
          return null;
      }
  
      /**
       * Request the record of {@link BluetoothActivityEnergyInfo} object that
       * has the activity and energy info. This can be used to ascertain what
       * the controller has been up to, since the last sample.
       *
       * A null value for the activity info object may be sent if the bluetooth service is
       * unreachable or the device does not support reporting such information.
       *
       * @param result The callback to which to send the activity info.
       * @hide
       */
      public void requestControllerActivityEnergyInfo(ResultReceiver result) {
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  mService.requestActivityInfo(result);
                  result = null;
              }
          } catch (RemoteException e) {
              Log.e(TAG, "getControllerActivityEnergyInfoCallback: " + e);
          } finally {
              mServiceLock.readLock().unlock();
              if (result != null) {
                  // Only send an immediate result if we failed.
                  result.send(0, null);
              }
          }
      }
  
      /**
       * Return the set of {@link BluetoothDevice} objects that are bonded
       * (paired) to the local adapter.
       * <p>If Bluetooth state is not {@link #STATE_ON}, this API
       * will return an empty set. After turning on Bluetooth,
       * wait for {@link #ACTION_STATE_CHANGED} with {@link #STATE_ON}
       * to get the updated value.
       *
       * @return unmodifiable set of {@link BluetoothDevice}, or null on error
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public Set<BluetoothDevice> getBondedDevices() {
          if (getState() != STATE_ON) {
              return toDeviceSet(new BluetoothDevice[0]);
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return toDeviceSet(mService.getBondedDevices());
              }
              return toDeviceSet(new BluetoothDevice[0]);
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return null;
      }
  
      /**
       * Gets the currently supported profiles by the adapter.
       *
       * <p> This can be used to check whether a profile is supported before attempting
       * to connect to its respective proxy.
       *
       * @return a list of integers indicating the ids of supported profiles as defined in {@link
       * BluetoothProfile}.
       * @hide
       */
      public List<Integer> getSupportedProfiles() {
          final ArrayList<Integer> supportedProfiles = new ArrayList<Integer>();
  
          try {
              synchronized (mManagerCallback) {
                  if (mService != null) {
                      final long supportedProfilesBitMask = mService.getSupportedProfiles();
  
                      for (int i = 0; i <= BluetoothProfile.MAX_PROFILE_ID; i++) {
                          if ((supportedProfilesBitMask & (1 << i)) != 0) {
                              supportedProfiles.add(i);
                          }
                      }
                  } else {
                      // Bluetooth is disabled. Just fill in known supported Profiles
                      if (isHearingAidProfileSupported()) {
                          supportedProfiles.add(BluetoothProfile.HEARING_AID);
                      }
                  }
              }
          } catch (RemoteException e) {
              Log.e(TAG, "getSupportedProfiles:", e);
          }
          return supportedProfiles;
      }
  
      /**
       * Get the current connection state of the local Bluetooth adapter.
       * This can be used to check whether the local Bluetooth adapter is connected
       * to any profile of any other remote Bluetooth Device.
       *
       * <p> Use this function along with {@link #ACTION_CONNECTION_STATE_CHANGED}
       * intent to get the connection state of the adapter.
       *
       * @return One of {@link #STATE_CONNECTED}, {@link #STATE_DISCONNECTED}, {@link
       * #STATE_CONNECTING} or {@link #STATE_DISCONNECTED}
       * @hide
       */
      @UnsupportedAppUsage
      public int getConnectionState() {
          if (getState() != STATE_ON) {
              return BluetoothAdapter.STATE_DISCONNECTED;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.getAdapterConnectionState();
              }
          } catch (RemoteException e) {
              Log.e(TAG, "getConnectionState:", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return BluetoothAdapter.STATE_DISCONNECTED;
      }
  
      /**
       * Get the current connection state of a profile.
       * This function can be used to check whether the local Bluetooth adapter
       * is connected to any remote device for a specific profile.
       * Profile can be one of {@link BluetoothProfile#HEADSET}, {@link BluetoothProfile#A2DP}.
       *
       * <p> Return value can be one of
       * {@link BluetoothProfile#STATE_DISCONNECTED},
       * {@link BluetoothProfile#STATE_CONNECTING},
       * {@link BluetoothProfile#STATE_CONNECTED},
       * {@link BluetoothProfile#STATE_DISCONNECTING}
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public int getProfileConnectionState(int profile) {
          if (getState() != STATE_ON) {
              return BluetoothProfile.STATE_DISCONNECTED;
          }
          try {
              mServiceLock.readLock().lock();
              if (mService != null) {
                  return mService.getProfileConnectionState(profile);
              }
          } catch (RemoteException e) {
              Log.e(TAG, "getProfileConnectionState:", e);
          } finally {
              mServiceLock.readLock().unlock();
          }
          return BluetoothProfile.STATE_DISCONNECTED;
      }
  
      /**
       * Create a listening, secure RFCOMM Bluetooth socket.
       * <p>A remote device connecting to this socket will be authenticated and
       * communication on this socket will be encrypted.
       * <p>Use {@link BluetoothServerSocket#accept} to retrieve incoming
       * connections from a listening {@link BluetoothServerSocket}.
       * <p>Valid RFCOMM channels are in range 1 to 30.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH_ADMIN}
       *
       * @param channel RFCOMM channel to listen on
       * @return a listening RFCOMM BluetoothServerSocket
       * @throws IOException on error, for example Bluetooth not available, or insufficient
       * permissions, or channel in use.
       * @hide
       */
      public BluetoothServerSocket listenUsingRfcommOn(int channel) throws IOException {
          return listenUsingRfcommOn(channel, false, false);
      }
  
      /**
       * Create a listening, secure RFCOMM Bluetooth socket.
       * <p>A remote device connecting to this socket will be authenticated and
       * communication on this socket will be encrypted.
       * <p>Use {@link BluetoothServerSocket#accept} to retrieve incoming
       * connections from a listening {@link BluetoothServerSocket}.
       * <p>Valid RFCOMM channels are in range 1 to 30.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH_ADMIN}
       * <p>To auto assign a channel without creating a SDP record use
       * {@link #SOCKET_CHANNEL_AUTO_STATIC_NO_SDP} as channel number.
       *
       * @param channel RFCOMM channel to listen on
       * @param mitm enforce man-in-the-middle protection for authentication.
       * @param min16DigitPin enforce a pin key length og minimum 16 digit for sec mode 2
       * connections.
       * @return a listening RFCOMM BluetoothServerSocket
       * @throws IOException on error, for example Bluetooth not available, or insufficient
       * permissions, or channel in use.
       * @hide
       */
      @UnsupportedAppUsage
      public BluetoothServerSocket listenUsingRfcommOn(int channel, boolean mitm,
              boolean min16DigitPin) throws IOException {
          BluetoothServerSocket socket =
                  new BluetoothServerSocket(BluetoothSocket.TYPE_RFCOMM, true, true, channel, mitm,
                          min16DigitPin);
          int errno = socket.mSocket.bindListen();
          if (channel == SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
              socket.setChannel(socket.mSocket.getPort());
          }
          if (errno != 0) {
              //TODO(BT): Throw the same exception error code
              // that the previous code was using.
              //socket.mSocket.throwErrnoNative(errno);
              throw new IOException("Error: " + errno);
          }
          return socket;
      }
  
      /**
       * Create a listening, secure RFCOMM Bluetooth socket with Service Record.
       * <p>A remote device connecting to this socket will be authenticated and
       * communication on this socket will be encrypted.
       * <p>Use {@link BluetoothServerSocket#accept} to retrieve incoming
       * connections from a listening {@link BluetoothServerSocket}.
       * <p>The system will assign an unused RFCOMM channel to listen on.
       * <p>The system will also register a Service Discovery
       * Protocol (SDP) record with the local SDP server containing the specified
       * UUID, service name, and auto-assigned channel. Remote Bluetooth devices
       * can use the same UUID to query our SDP server and discover which channel
       * to connect to. This SDP record will be removed when this socket is
       * closed, or if this application closes unexpectedly.
       * <p>Use {@link BluetoothDevice#createRfcommSocketToServiceRecord} to
       * connect to this socket from another device using the same {@link UUID}.
       *
       * @param name service name for SDP record
       * @param uuid uuid for SDP record
       * @return a listening RFCOMM BluetoothServerSocket
       * @throws IOException on error, for example Bluetooth not available, or insufficient
       * permissions, or channel in use.
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public BluetoothServerSocket listenUsingRfcommWithServiceRecord(String name, UUID uuid)
              throws IOException {
          return createNewRfcommSocketAndRecord(name, uuid, true, true);
      }
  
      /**
       * Create a listening, insecure RFCOMM Bluetooth socket with Service Record.
       * <p>The link key is not required to be authenticated, i.e the communication may be
       * vulnerable to Man In the Middle attacks. For Bluetooth 2.1 devices,
       * the link will be encrypted, as encryption is mandartory.
       * For legacy devices (pre Bluetooth 2.1 devices) the link will not
       * be encrypted. Use {@link #listenUsingRfcommWithServiceRecord}, if an
       * encrypted and authenticated communication channel is desired.
       * <p>Use {@link BluetoothServerSocket#accept} to retrieve incoming
       * connections from a listening {@link BluetoothServerSocket}.
       * <p>The system will assign an unused RFCOMM channel to listen on.
       * <p>The system will also register a Service Discovery
       * Protocol (SDP) record with the local SDP server containing the specified
       * UUID, service name, and auto-assigned channel. Remote Bluetooth devices
       * can use the same UUID to query our SDP server and discover which channel
       * to connect to. This SDP record will be removed when this socket is
       * closed, or if this application closes unexpectedly.
       * <p>Use {@link BluetoothDevice#createRfcommSocketToServiceRecord} to
       * connect to this socket from another device using the same {@link UUID}.
       *
       * @param name service name for SDP record
       * @param uuid uuid for SDP record
       * @return a listening RFCOMM BluetoothServerSocket
       * @throws IOException on error, for example Bluetooth not available, or insufficient
       * permissions, or channel in use.
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public BluetoothServerSocket listenUsingInsecureRfcommWithServiceRecord(String name, UUID uuid)
              throws IOException {
          return createNewRfcommSocketAndRecord(name, uuid, false, false);
      }
  
      /**
       * Create a listening, encrypted,
       * RFCOMM Bluetooth socket with Service Record.
       * <p>The link will be encrypted, but the link key is not required to be authenticated
       * i.e the communication is vulnerable to Man In the Middle attacks. Use
       * {@link #listenUsingRfcommWithServiceRecord}, to ensure an authenticated link key.
       * <p> Use this socket if authentication of link key is not possible.
       * For example, for Bluetooth 2.1 devices, if any of the devices does not have
       * an input and output capability or just has the ability to display a numeric key,
       * a secure socket connection is not possible and this socket can be used.
       * Use {@link #listenUsingInsecureRfcommWithServiceRecord}, if encryption is not required.
       * For Bluetooth 2.1 devices, the link will be encrypted, as encryption is mandartory.
       * For more details, refer to the Security Model section 5.2 (vol 3) of
       * Bluetooth Core Specification version 2.1 + EDR.
       * <p>Use {@link BluetoothServerSocket#accept} to retrieve incoming
       * connections from a listening {@link BluetoothServerSocket}.
       * <p>The system will assign an unused RFCOMM channel to listen on.
       * <p>The system will also register a Service Discovery
       * Protocol (SDP) record with the local SDP server containing the specified
       * UUID, service name, and auto-assigned channel. Remote Bluetooth devices
       * can use the same UUID to query our SDP server and discover which channel
       * to connect to. This SDP record will be removed when this socket is
       * closed, or if this application closes unexpectedly.
       * <p>Use {@link BluetoothDevice#createRfcommSocketToServiceRecord} to
       * connect to this socket from another device using the same {@link UUID}.
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH}
       *
       * @param name service name for SDP record
       * @param uuid uuid for SDP record
       * @return a listening RFCOMM BluetoothServerSocket
       * @throws IOException on error, for example Bluetooth not available, or insufficient
       * permissions, or channel in use.
       * @hide
       */
      @UnsupportedAppUsage
      public BluetoothServerSocket listenUsingEncryptedRfcommWithServiceRecord(String name, UUID uuid)
              throws IOException {
          return createNewRfcommSocketAndRecord(name, uuid, false, true);
      }
  
  
      private BluetoothServerSocket createNewRfcommSocketAndRecord(String name, UUID uuid,
              boolean auth, boolean encrypt) throws IOException {
          BluetoothServerSocket socket;
          socket = new BluetoothServerSocket(BluetoothSocket.TYPE_RFCOMM, auth, encrypt,
                  new ParcelUuid(uuid));
          socket.setServiceName(name);
          int errno = socket.mSocket.bindListen();
          if (errno != 0) {
              //TODO(BT): Throw the same exception error code
              // that the previous code was using.
              //socket.mSocket.throwErrnoNative(errno);
              throw new IOException("Error: " + errno);
          }
          return socket;
      }
  
      /**
       * Construct an unencrypted, unauthenticated, RFCOMM server socket.
       * Call #accept to retrieve connections to this socket.
       *
       * @return An RFCOMM BluetoothServerSocket
       * @throws IOException On error, for example Bluetooth not available, or insufficient
       * permissions.
       * @hide
       */
      public BluetoothServerSocket listenUsingInsecureRfcommOn(int port) throws IOException {
          BluetoothServerSocket socket =
                  new BluetoothServerSocket(BluetoothSocket.TYPE_RFCOMM, false, false, port);
          int errno = socket.mSocket.bindListen();
          if (port == SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
              socket.setChannel(socket.mSocket.getPort());
          }
          if (errno != 0) {
              //TODO(BT): Throw the same exception error code
              // that the previous code was using.
              //socket.mSocket.throwErrnoNative(errno);
              throw new IOException("Error: " + errno);
          }
          return socket;
      }
  
      /**
       * Construct an encrypted, RFCOMM server socket.
       * Call #accept to retrieve connections to this socket.
       *
       * @return An RFCOMM BluetoothServerSocket
       * @throws IOException On error, for example Bluetooth not available, or insufficient
       * permissions.
       * @hide
       */
      public BluetoothServerSocket listenUsingEncryptedRfcommOn(int port) throws IOException {
          BluetoothServerSocket socket =
                  new BluetoothServerSocket(BluetoothSocket.TYPE_RFCOMM, false, true, port);
          int errno = socket.mSocket.bindListen();
          if (port == SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
              socket.setChannel(socket.mSocket.getPort());
          }
          if (errno < 0) {
              //TODO(BT): Throw the same exception error code
              // that the previous code was using.
              //socket.mSocket.throwErrnoNative(errno);
              throw new IOException("Error: " + errno);
          }
          return socket;
      }
  
      /**
       * Construct a SCO server socket.
       * Call #accept to retrieve connections to this socket.
       *
       * @return A SCO BluetoothServerSocket
       * @throws IOException On error, for example Bluetooth not available, or insufficient
       * permissions.
       * @hide
       */
      public static BluetoothServerSocket listenUsingScoOn() throws IOException {
          BluetoothServerSocket socket =
                  new BluetoothServerSocket(BluetoothSocket.TYPE_SCO, false, false, -1);
          int errno = socket.mSocket.bindListen();
          if (errno < 0) {
              //TODO(BT): Throw the same exception error code
              // that the previous code was using.
              //socket.mSocket.throwErrnoNative(errno);
          }
          return socket;
      }
  
      /**
       * Construct an encrypted, authenticated, L2CAP server socket.
       * Call #accept to retrieve connections to this socket.
       * <p>To auto assign a port without creating a SDP record use
       * {@link #SOCKET_CHANNEL_AUTO_STATIC_NO_SDP} as port number.
       *
       * @param port the PSM to listen on
       * @param mitm enforce man-in-the-middle protection for authentication.
       * @param min16DigitPin enforce a pin key length og minimum 16 digit for sec mode 2
       * connections.
       * @return An L2CAP BluetoothServerSocket
       * @throws IOException On error, for example Bluetooth not available, or insufficient
       * permissions.
       * @hide
       */
      public BluetoothServerSocket listenUsingL2capOn(int port, boolean mitm, boolean min16DigitPin)
              throws IOException {
          BluetoothServerSocket socket =
                  new BluetoothServerSocket(BluetoothSocket.TYPE_L2CAP, true, true, port, mitm,
                          min16DigitPin);
          int errno = socket.mSocket.bindListen();
          if (port == SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
              int assignedChannel = socket.mSocket.getPort();
              if (DBG) Log.d(TAG, "listenUsingL2capOn: set assigned channel to " + assignedChannel);
              socket.setChannel(assignedChannel);
          }
          if (errno != 0) {
              //TODO(BT): Throw the same exception error code
              // that the previous code was using.
              //socket.mSocket.throwErrnoNative(errno);
              throw new IOException("Error: " + errno);
          }
          return socket;
      }
  
      /**
       * Construct an encrypted, authenticated, L2CAP server socket.
       * Call #accept to retrieve connections to this socket.
       * <p>To auto assign a port without creating a SDP record use
       * {@link #SOCKET_CHANNEL_AUTO_STATIC_NO_SDP} as port number.
       *
       * @param port the PSM to listen on
       * @return An L2CAP BluetoothServerSocket
       * @throws IOException On error, for example Bluetooth not available, or insufficient
       * permissions.
       * @hide
       */
      public BluetoothServerSocket listenUsingL2capOn(int port) throws IOException {
          return listenUsingL2capOn(port, false, false);
      }
  
  
      /**
       * Construct an insecure L2CAP server socket.
       * Call #accept to retrieve connections to this socket.
       * <p>To auto assign a port without creating a SDP record use
       * {@link #SOCKET_CHANNEL_AUTO_STATIC_NO_SDP} as port number.
       *
       * @param port the PSM to listen on
       * @return An L2CAP BluetoothServerSocket
       * @throws IOException On error, for example Bluetooth not available, or insufficient
       * permissions.
       * @hide
       */
      public BluetoothServerSocket listenUsingInsecureL2capOn(int port) throws IOException {
          Log.d(TAG, "listenUsingInsecureL2capOn: port=" + port);
          BluetoothServerSocket socket =
                  new BluetoothServerSocket(BluetoothSocket.TYPE_L2CAP, false, false, port, false,
                                            false);
          int errno = socket.mSocket.bindListen();
          if (port == SOCKET_CHANNEL_AUTO_STATIC_NO_SDP) {
              int assignedChannel = socket.mSocket.getPort();
              if (DBG) {
                  Log.d(TAG, "listenUsingInsecureL2capOn: set assigned channel to "
                          + assignedChannel);
              }
              socket.setChannel(assignedChannel);
          }
          if (errno != 0) {
              //TODO(BT): Throw the same exception error code
              // that the previous code was using.
              //socket.mSocket.throwErrnoNative(errno);
              throw new IOException("Error: " + errno);
          }
          return socket;
  
      }
  
      /**
       * Read the local Out of Band Pairing Data
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH}
       *
       * @return Pair<byte[], byte[]> of Hash and Randomizer
       * @hide
       */
      public Pair<byte[], byte[]> readOutOfBandData() {
          return null;
      }
  
      /**
       * Get the profile proxy object associated with the profile.
       *
       * <p>Profile can be one of {@link BluetoothProfile#HEADSET}, {@link BluetoothProfile#A2DP},
       * {@link BluetoothProfile#GATT}, {@link BluetoothProfile#HEARING_AID}, or {@link
       * BluetoothProfile#GATT_SERVER}. Clients must implement {@link
       * BluetoothProfile.ServiceListener} to get notified of the connection status and to get the
       * proxy object.
       *
       * @param context Context of the application
       * @param listener The service Listener for connection callbacks.
       * @param profile The Bluetooth profile; either {@link BluetoothProfile#HEADSET},
       * {@link BluetoothProfile#A2DP}, {@link BluetoothProfile#GATT}, {@link
       * BluetoothProfile#HEARING_AID} or {@link BluetoothProfile#GATT_SERVER}.
       * @return true on success, false on error
       */
      public boolean getProfileProxy(Context context, BluetoothProfile.ServiceListener listener,
              int profile) {
          if (context == null || listener == null) {
              return false;
          }
  
          if (profile == BluetoothProfile.HEADSET) {
              BluetoothHeadset headset = new BluetoothHeadset(context, listener);
              return true;
          } else if (profile == BluetoothProfile.A2DP) {
              BluetoothA2dp a2dp = new BluetoothA2dp(context, listener);
              return true;
          } else if (profile == BluetoothProfile.A2DP_SINK) {
              BluetoothA2dpSink a2dpSink = new BluetoothA2dpSink(context, listener);
              return true;
          } else if (profile == BluetoothProfile.AVRCP_CONTROLLER) {
              BluetoothAvrcpController avrcp = new BluetoothAvrcpController(context, listener);
              return true;
          } else if (profile == BluetoothProfile.HID_HOST) {
              BluetoothHidHost iDev = new BluetoothHidHost(context, listener);
              return true;
          } else if (profile == BluetoothProfile.PAN) {
              BluetoothPan pan = new BluetoothPan(context, listener);
              return true;
          } else if (profile == BluetoothProfile.HEALTH) {
              Log.e(TAG, "getProfileProxy(): BluetoothHealth is deprecated");
              return false;
          } else if (profile == BluetoothProfile.MAP) {
              BluetoothMap map = new BluetoothMap(context, listener);
              return true;
          } else if (profile == BluetoothProfile.HEADSET_CLIENT) {
              BluetoothHeadsetClient headsetClient = new BluetoothHeadsetClient(context, listener);
              return true;
          } else if (profile == BluetoothProfile.SAP) {
              BluetoothSap sap = new BluetoothSap(context, listener);
              return true;
          } else if (profile == BluetoothProfile.PBAP_CLIENT) {
              BluetoothPbapClient pbapClient = new BluetoothPbapClient(context, listener);
              return true;
          } else if (profile == BluetoothProfile.MAP_CLIENT) {
              BluetoothMapClient mapClient = new BluetoothMapClient(context, listener);
              return true;
          } else if (profile == BluetoothProfile.HID_DEVICE) {
              BluetoothHidDevice hidDevice = new BluetoothHidDevice(context, listener);
              return true;
          } else if (profile == BluetoothProfile.HEARING_AID) {
              if (isHearingAidProfileSupported()) {
                  BluetoothHearingAid hearingAid = new BluetoothHearingAid(context, listener);
                  return true;
              }
              return false;
          } else {
              return false;
          }
      }
  
      /**
       * Close the connection of the profile proxy to the Service.
       *
       * <p> Clients should call this when they are no longer using
       * the proxy obtained from {@link #getProfileProxy}.
       * Profile can be one of  {@link BluetoothProfile#HEADSET} or {@link BluetoothProfile#A2DP}
       *
       * @param profile
       * @param proxy Profile proxy object
       */
      public void closeProfileProxy(int profile, BluetoothProfile proxy) {
          if (proxy == null) {
              return;
          }
  
          switch (profile) {
              case BluetoothProfile.HEADSET:
                  BluetoothHeadset headset = (BluetoothHeadset) proxy;
                  headset.close();
                  break;
              case BluetoothProfile.A2DP:
                  BluetoothA2dp a2dp = (BluetoothA2dp) proxy;
                  a2dp.close();
                  break;
              case BluetoothProfile.A2DP_SINK:
                  BluetoothA2dpSink a2dpSink = (BluetoothA2dpSink) proxy;
                  a2dpSink.close();
                  break;
              case BluetoothProfile.AVRCP_CONTROLLER:
                  BluetoothAvrcpController avrcp = (BluetoothAvrcpController) proxy;
                  avrcp.close();
                  break;
              case BluetoothProfile.HID_HOST:
                  BluetoothHidHost iDev = (BluetoothHidHost) proxy;
                  iDev.close();
                  break;
              case BluetoothProfile.PAN:
                  BluetoothPan pan = (BluetoothPan) proxy;
                  pan.close();
                  break;
              case BluetoothProfile.GATT:
                  BluetoothGatt gatt = (BluetoothGatt) proxy;
                  gatt.close();
                  break;
              case BluetoothProfile.GATT_SERVER:
                  BluetoothGattServer gattServer = (BluetoothGattServer) proxy;
                  gattServer.close();
                  break;
              case BluetoothProfile.MAP:
                  BluetoothMap map = (BluetoothMap) proxy;
                  map.close();
                  break;
              case BluetoothProfile.HEADSET_CLIENT:
                  BluetoothHeadsetClient headsetClient = (BluetoothHeadsetClient) proxy;
                  headsetClient.close();
                  break;
              case BluetoothProfile.SAP:
                  BluetoothSap sap = (BluetoothSap) proxy;
                  sap.close();
                  break;
              case BluetoothProfile.PBAP_CLIENT:
                  BluetoothPbapClient pbapClient = (BluetoothPbapClient) proxy;
                  pbapClient.close();
                  break;
              case BluetoothProfile.MAP_CLIENT:
                  BluetoothMapClient mapClient = (BluetoothMapClient) proxy;
                  mapClient.close();
                  break;
              case BluetoothProfile.HID_DEVICE:
                  BluetoothHidDevice hidDevice = (BluetoothHidDevice) proxy;
                  hidDevice.close();
                  break;
              case BluetoothProfile.HEARING_AID:
                  BluetoothHearingAid hearingAid = (BluetoothHearingAid) proxy;
                  hearingAid.close();
          }
      }
  
      private final IBluetoothManagerCallback mManagerCallback =
              new IBluetoothManagerCallback.Stub() {
                  public void onBluetoothServiceUp(IBluetooth bluetoothService) {
                      if (DBG) {
                          Log.d(TAG, "onBluetoothServiceUp: " + bluetoothService);
                      }
  
                      mServiceLock.writeLock().lock();
                      mService = bluetoothService;
                      mServiceLock.writeLock().unlock();
  
                      synchronized (mProxyServiceStateCallbacks) {
                          for (IBluetoothManagerCallback cb : mProxyServiceStateCallbacks) {
                              try {
                                  if (cb != null) {
                                      cb.onBluetoothServiceUp(bluetoothService);
                                  } else {
                                      Log.d(TAG, "onBluetoothServiceUp: cb is null!");
                                  }
                              } catch (Exception e) {
                                  Log.e(TAG, "", e);
                              }
                          }
                      }
                      synchronized (sMetadataListeners) {
                          sMetadataListeners.forEach((device, pair) -> {
                              try {
                                  mService.registerMetadataListener(sBluetoothMetadataListener,
                                          device);
                              } catch (RemoteException e) {
                                  Log.e(TAG, "Failed to register metadata listener", e);
                              }
                          });
                      }
                  }
  
                  public void onBluetoothServiceDown() {
                      if (DBG) {
                          Log.d(TAG, "onBluetoothServiceDown: " + mService);
                      }
  
                      try {
                          mServiceLock.writeLock().lock();
                          mService = null;
                          if (mLeScanClients != null) {
                              mLeScanClients.clear();
                          }
                          if (sBluetoothLeAdvertiser != null) {
                              sBluetoothLeAdvertiser.cleanup();
                          }
                          if (sBluetoothLeScanner != null) {
                              sBluetoothLeScanner.cleanup();
                          }
                      } finally {
                          mServiceLock.writeLock().unlock();
                      }
  
                      synchronized (mProxyServiceStateCallbacks) {
                          for (IBluetoothManagerCallback cb : mProxyServiceStateCallbacks) {
                              try {
                                  if (cb != null) {
                                      cb.onBluetoothServiceDown();
                                  } else {
                                      Log.d(TAG, "onBluetoothServiceDown: cb is null!");
                                  }
                              } catch (Exception e) {
                                  Log.e(TAG, "", e);
                              }
                          }
                      }
                  }
  
                  public void onBrEdrDown() {
                      if (VDBG) {
                          Log.i(TAG, "onBrEdrDown: " + mService);
                      }
                  }
              };
  
      /**
       * Enable the Bluetooth Adapter, but don't auto-connect devices
       * and don't persist state. Only for use by system applications.
       *
       * @hide
       */
      @SystemApi
      @RequiresPermission(android.Manifest.permission.BLUETOOTH_ADMIN)
      public boolean enableNoAutoConnect() {
          if (isEnabled()) {
              if (DBG) {
                  Log.d(TAG, "enableNoAutoConnect(): BT already enabled!");
              }
              return true;
          }
          try {
              return mManagerService.enableNoAutoConnect(ActivityThread.currentPackageName());
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          }
          return false;
      }
  
      /**
       * Enable control of the Bluetooth Adapter for a single application.
       *
       * <p>Some applications need to use Bluetooth for short periods of time to
       * transfer data but don't want all the associated implications like
       * automatic connection to headsets etc.
       *
       * <p> Multiple applications can call this. This is reference counted and
       * Bluetooth disabled only when no one else is using it. There will be no UI
       * shown to the user while bluetooth is being enabled. Any user action will
       * override this call. For example, if user wants Bluetooth on and the last
       * user of this API wanted to disable Bluetooth, Bluetooth will not be
       * turned off.
       *
       * <p> This API is only meant to be used by internal applications. Third
       * party applications but use {@link #enable} and {@link #disable} APIs.
       *
       * <p> If this API returns true, it means the callback will be called.
       * The callback will be called with the current state of Bluetooth.
       * If the state is not what was requested, an internal error would be the
       * reason. If Bluetooth is already on and if this function is called to turn
       * it on, the api will return true and a callback will be called.
       *
       * <p>Requires {@link android.Manifest.permission#BLUETOOTH}
       *
       * @param on True for on, false for off.
       * @param callback The callback to notify changes to the state.
       * @hide
       */
      public boolean changeApplicationBluetoothState(boolean on,
              BluetoothStateChangeCallback callback) {
          return false;
      }
  
      /**
       * @hide
       */
      public interface BluetoothStateChangeCallback {
          /**
           * @hide
           */
          void onBluetoothStateChange(boolean on);
      }
  
      /**
       * @hide
       */
      public class StateChangeCallbackWrapper extends IBluetoothStateChangeCallback.Stub {
          private BluetoothStateChangeCallback mCallback;
  
          StateChangeCallbackWrapper(BluetoothStateChangeCallback callback) {
              mCallback = callback;
          }
  
          @Override
          public void onBluetoothStateChange(boolean on) {
              mCallback.onBluetoothStateChange(on);
          }
      }
  
      private Set<BluetoothDevice> toDeviceSet(BluetoothDevice[] devices) {
          Set<BluetoothDevice> deviceSet = new HashSet<BluetoothDevice>(Arrays.asList(devices));
          return Collections.unmodifiableSet(deviceSet);
      }
  
      protected void finalize() throws Throwable {
          try {
              mManagerService.unregisterAdapter(mManagerCallback);
          } catch (RemoteException e) {
              Log.e(TAG, "", e);
          } finally {
              super.finalize();
          }
      }
  
  
      /**
       * Validate a String Bluetooth address, such as "00:43:A8:23:10:F0"
       * <p>Alphabetic characters must be uppercase to be valid.
       *
       * @param address Bluetooth address as string
       * @return true if the address is valid, false otherwise
       */
      public static boolean checkBluetoothAddress(String address) {
          if (address == null || address.length() != ADDRESS_LENGTH) {
              return false;
          }
          for (int i = 0; i < ADDRESS_LENGTH; i++) {
              char c = address.charAt(i);
              switch (i % 3) {
                  case 0:
                  case 1:
                      if ((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F')) {
                          // hex character, OK
                          break;
                      }
                      return false;
                  case 2:
                      if (c == ':') {
                          break;  // OK
                      }
                      return false;
              }
          }
          return true;
      }
  
      @UnsupportedAppUsage
      /*package*/ IBluetoothManager getBluetoothManager() {
          return mManagerService;
      }
  
      private final ArrayList<IBluetoothManagerCallback> mProxyServiceStateCallbacks =
              new ArrayList<IBluetoothManagerCallback>();
  
      @UnsupportedAppUsage
      /*package*/ IBluetooth getBluetoothService(IBluetoothManagerCallback cb) {
          synchronized (mProxyServiceStateCallbacks) {
              if (cb == null) {
                  Log.w(TAG, "getBluetoothService() called with no BluetoothManagerCallback");
              } else if (!mProxyServiceStateCallbacks.contains(cb)) {
                  mProxyServiceStateCallbacks.add(cb);
              }
          }
          return mService;
      }
  
      /*package*/ void removeServiceStateCallback(IBluetoothManagerCallback cb) {
          synchronized (mProxyServiceStateCallbacks) {
              mProxyServiceStateCallbacks.remove(cb);
          }
      }
  
      /**
       * Callback interface used to deliver LE scan results.
       *
       * @see #startLeScan(LeScanCallback)
       * @see #startLeScan(UUID[], LeScanCallback)
       */
      public interface LeScanCallback {
          /**
           * Callback reporting an LE device found during a device scan initiated
           * by the {@link BluetoothAdapter#startLeScan} function.
           *
           * @param device Identifies the remote device
           * @param rssi The RSSI value for the remote device as reported by the Bluetooth hardware. 0
           * if no RSSI value is available.
           * @param scanRecord The content of the advertisement record offered by the remote device.
           */
          void onLeScan(BluetoothDevice device, int rssi, byte[] scanRecord);
      }
  
      /**
       * Starts a scan for Bluetooth LE devices.
       *
       * <p>Results of the scan are reported using the
       * {@link LeScanCallback#onLeScan} callback.
       *
       * @param callback the callback LE scan results are delivered
       * @return true, if the scan was started successfully
       * @deprecated use {@link BluetoothLeScanner#startScan(List, ScanSettings, ScanCallback)}
       * instead.
       */
      @Deprecated
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      public boolean startLeScan(LeScanCallback callback) {
          return startLeScan(null, callback);
      }
  
      /**
       * Starts a scan for Bluetooth LE devices, looking for devices that
       * advertise given services.
       *
       * <p>Devices which advertise all specified services are reported using the
       * {@link LeScanCallback#onLeScan} callback.
       *
       * @param serviceUuids Array of services to look for
       * @param callback the callback LE scan results are delivered
       * @return true, if the scan was started successfully
       * @deprecated use {@link BluetoothLeScanner#startScan(List, ScanSettings, ScanCallback)}
       * instead.
       */
      @Deprecated
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      public boolean startLeScan(final UUID[] serviceUuids, final LeScanCallback callback) {
          if (DBG) {
              Log.d(TAG, "startLeScan(): " + Arrays.toString(serviceUuids));
          }
          if (callback == null) {
              if (DBG) {
                  Log.e(TAG, "startLeScan: null callback");
              }
              return false;
          }
          BluetoothLeScanner scanner = getBluetoothLeScanner();
          if (scanner == null) {
              if (DBG) {
                  Log.e(TAG, "startLeScan: cannot get BluetoothLeScanner");
              }
              return false;
          }
  
          synchronized (mLeScanClients) {
              if (mLeScanClients.containsKey(callback)) {
                  if (DBG) {
                      Log.e(TAG, "LE Scan has already started");
                  }
                  return false;
              }
  
              try {
                  IBluetoothGatt iGatt = mManagerService.getBluetoothGatt();
                  if (iGatt == null) {
                      // BLE is not supported
                      return false;
                  }
  
                  ScanCallback scanCallback = new ScanCallback() {
                      @Override
                      public void onScanResult(int callbackType, ScanResult result) {
                          if (callbackType != ScanSettings.CALLBACK_TYPE_ALL_MATCHES) {
                              // Should not happen.
                              Log.e(TAG, "LE Scan has already started");
                              return;
                          }
                          ScanRecord scanRecord = result.getScanRecord();
                          if (scanRecord == null) {
                              return;
                          }
                          if (serviceUuids != null) {
                              List<ParcelUuid> uuids = new ArrayList<ParcelUuid>();
                              for (UUID uuid : serviceUuids) {
                                  uuids.add(new ParcelUuid(uuid));
                              }
                              List<ParcelUuid> scanServiceUuids = scanRecord.getServiceUuids();
                              if (scanServiceUuids == null || !scanServiceUuids.containsAll(uuids)) {
                                  if (DBG) {
                                      Log.d(TAG, "uuids does not match");
                                  }
                                  return;
                              }
                          }
                          callback.onLeScan(result.getDevice(), result.getRssi(),
                                  scanRecord.getBytes());
                      }
                  };
                  ScanSettings settings = new ScanSettings.Builder().setCallbackType(
                          ScanSettings.CALLBACK_TYPE_ALL_MATCHES)
                          .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
                          .build();
  
                  List<ScanFilter> filters = new ArrayList<ScanFilter>();
                  if (serviceUuids != null && serviceUuids.length > 0) {
                      // Note scan filter does not support matching an UUID array so we put one
                      // UUID to hardware and match the whole array in callback.
                      ScanFilter filter =
                              new ScanFilter.Builder().setServiceUuid(new ParcelUuid(serviceUuids[0]))
                                      .build();
                      filters.add(filter);
                  }
                  scanner.startScan(filters, settings, scanCallback);
  
                  mLeScanClients.put(callback, scanCallback);
                  return true;
  
              } catch (RemoteException e) {
                  Log.e(TAG, "", e);
              }
          }
          return false;
      }
  
      /**
       * Stops an ongoing Bluetooth LE device scan.
       *
       * @param callback used to identify which scan to stop must be the same handle used to start the
       * scan
       * @deprecated Use {@link BluetoothLeScanner#stopScan(ScanCallback)} instead.
       */
      @Deprecated
      @RequiresPermission(Manifest.permission.BLUETOOTH_ADMIN)
      public void stopLeScan(LeScanCallback callback) {
          if (DBG) {
              Log.d(TAG, "stopLeScan()");
          }
          BluetoothLeScanner scanner = getBluetoothLeScanner();
          if (scanner == null) {
              return;
          }
          synchronized (mLeScanClients) {
              ScanCallback scanCallback = mLeScanClients.remove(callback);
              if (scanCallback == null) {
                  if (DBG) {
                      Log.d(TAG, "scan not started yet");
                  }
                  return;
              }
              scanner.stopScan(scanCallback);
          }
      }
  
      /**
       * Create a secure L2CAP Connection-oriented Channel (CoC) {@link BluetoothServerSocket} and
       * assign a dynamic protocol/service multiplexer (PSM) value. This socket can be used to listen
       * for incoming connections. The supported Bluetooth transport is LE only.
       * <p>A remote device connecting to this socket will be authenticated and communication on this
       * socket will be encrypted.
       * <p>Use {@link BluetoothServerSocket#accept} to retrieve incoming connections from a listening
       * {@link BluetoothServerSocket}.
       * <p>The system will assign a dynamic PSM value. This PSM value can be read from the {@link
       * BluetoothServerSocket#getPsm()} and this value will be released when this server socket is
       * closed, Bluetooth is turned off, or the application exits unexpectedly.
       * <p>The mechanism of disclosing the assigned dynamic PSM value to the initiating peer is
       * defined and performed by the application.
       * <p>Use {@link BluetoothDevice#createL2capChannel(int)} to connect to this server
       * socket from another Android device that is given the PSM value.
       *
       * @return an L2CAP CoC BluetoothServerSocket
       * @throws IOException on error, for example Bluetooth not available, or insufficient
       * permissions, or unable to start this CoC
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public @NonNull BluetoothServerSocket listenUsingL2capChannel()
              throws IOException {
          BluetoothServerSocket socket =
                              new BluetoothServerSocket(BluetoothSocket.TYPE_L2CAP_LE, true, true,
                                        SOCKET_CHANNEL_AUTO_STATIC_NO_SDP, false, false);
          int errno = socket.mSocket.bindListen();
          if (errno != 0) {
              throw new IOException("Error: " + errno);
          }
  
          int assignedPsm = socket.mSocket.getPort();
          if (assignedPsm == 0) {
              throw new IOException("Error: Unable to assign PSM value");
          }
          if (DBG) {
              Log.d(TAG, "listenUsingL2capChannel: set assigned PSM to "
                      + assignedPsm);
          }
          socket.setChannel(assignedPsm);
  
          return socket;
      }
  
      /**
       * TODO: Remove this hidden method once all the SL4A and other tests are updated to use the new
       * API name, listenUsingL2capChannel.
       * @hide
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public BluetoothServerSocket listenUsingL2capCoc(int transport)
              throws IOException {
          Log.e(TAG, "listenUsingL2capCoc: PLEASE USE THE OFFICIAL API, listenUsingL2capChannel");
          return listenUsingL2capChannel();
      }
  
      /**
       * Create an insecure L2CAP Connection-oriented Channel (CoC) {@link BluetoothServerSocket} and
       * assign a dynamic PSM value. This socket can be used to listen for incoming connections. The
       * supported Bluetooth transport is LE only.
       * <p>The link key is not required to be authenticated, i.e the communication may be vulnerable
       * to man-in-the-middle attacks. Use {@link #listenUsingL2capChannel}, if an encrypted and
       * authenticated communication channel is desired.
       * <p>Use {@link BluetoothServerSocket#accept} to retrieve incoming connections from a listening
       * {@link BluetoothServerSocket}.
       * <p>The system will assign a dynamic protocol/service multiplexer (PSM) value. This PSM value
       * can be read from the {@link BluetoothServerSocket#getPsm()} and this value will be released
       * when this server socket is closed, Bluetooth is turned off, or the application exits
       * unexpectedly.
       * <p>The mechanism of disclosing the assigned dynamic PSM value to the initiating peer is
       * defined and performed by the application.
       * <p>Use {@link BluetoothDevice#createInsecureL2capChannel(int)} to connect to this server
       * socket from another Android device that is given the PSM value.
       *
       * @return an L2CAP CoC BluetoothServerSocket
       * @throws IOException on error, for example Bluetooth not available, or insufficient
       * permissions, or unable to start this CoC
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public @NonNull BluetoothServerSocket listenUsingInsecureL2capChannel()
              throws IOException {
          BluetoothServerSocket socket =
                              new BluetoothServerSocket(BluetoothSocket.TYPE_L2CAP_LE, false, false,
                                        SOCKET_CHANNEL_AUTO_STATIC_NO_SDP, false, false);
          int errno = socket.mSocket.bindListen();
          if (errno != 0) {
              throw new IOException("Error: " + errno);
          }
  
          int assignedPsm = socket.mSocket.getPort();
          if (assignedPsm == 0) {
              throw new IOException("Error: Unable to assign PSM value");
          }
          if (DBG) {
              Log.d(TAG, "listenUsingInsecureL2capChannel: set assigned PSM to "
                      + assignedPsm);
          }
          socket.setChannel(assignedPsm);
  
          return socket;
      }
  
      /**
       * TODO: Remove this hidden method once all the SL4A and other tests are updated to use the new
       * API name, listenUsingInsecureL2capChannel.
       * @hide
       */
      @RequiresPermission(Manifest.permission.BLUETOOTH)
      public BluetoothServerSocket listenUsingInsecureL2capCoc(int transport)
              throws IOException {
          Log.e(TAG, "listenUsingInsecureL2capCoc: PLEASE USE THE OFFICIAL API, "
                      + "listenUsingInsecureL2capChannel");
          return listenUsingInsecureL2capChannel();
      }
  
      /**
       * Register a {@link #OnMetadataChangedListener} to receive update about metadata
       * changes for this {@link BluetoothDevice}.
       * Registration must be done when Bluetooth is ON and will last until
       * {@link #removeOnMetadataChangedListener(BluetoothDevice)} is called, even when Bluetooth
       * restarted in the middle.
       * All input parameters should not be null or {@link NullPointerException} will be triggered.
       * The same {@link BluetoothDevice} and {@link #OnMetadataChangedListener} pair can only be
       * registered once, double registration would cause {@link IllegalArgumentException}.
       *
       * @param device {@link BluetoothDevice} that will be registered
       * @param executor the executor for listener callback
       * @param listener {@link #OnMetadataChangedListener} that will receive asynchronous callbacks
       * @return true on success, false on error
       * @throws NullPointerException If one of {@code listener}, {@code device} or {@code executor}
       * is null.
       * @throws IllegalArgumentException The same {@link #OnMetadataChangedListener} and
       * {@link BluetoothDevice} are registered twice.
       * @hide
       */
      @SystemApi
      @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
      public boolean addOnMetadataChangedListener(@NonNull BluetoothDevice device,
              @NonNull Executor executor, @NonNull OnMetadataChangedListener listener) {
          if (DBG) Log.d(TAG, "addOnMetadataChangedListener()");
  
          final IBluetooth service = mService;
          if (service == null) {
              Log.e(TAG, "Bluetooth is not enabled. Cannot register metadata listener");
              return false;
          }
          if (listener == null) {
              throw new NullPointerException("listener is null");
          }
          if (device == null) {
              throw new NullPointerException("device is null");
          }
          if (executor == null) {
              throw new NullPointerException("executor is null");
          }
  
          synchronized (sMetadataListeners) {
              List<Pair<OnMetadataChangedListener, Executor>> listenerList =
                      sMetadataListeners.get(device);
              if (listenerList == null) {
                  // Create new listener/executor list for registeration
                  listenerList = new ArrayList<>();
                  sMetadataListeners.put(device, listenerList);
              } else {
                  // Check whether this device was already registed by the lisenter
                  if (listenerList.stream().anyMatch((pair) -> (pair.first.equals(listener)))) {
                      throw new IllegalArgumentException("listener was already regestered"
                              + " for the device");
                  }
              }
  
              Pair<OnMetadataChangedListener, Executor> listenerPair = new Pair(listener, executor);
              listenerList.add(listenerPair);
  
              boolean ret = false;
              try {
                  ret = service.registerMetadataListener(sBluetoothMetadataListener, device);
              } catch (RemoteException e) {
                  Log.e(TAG, "registerMetadataListener fail", e);
              } finally {
                  if (!ret) {
                      // Remove listener registered earlier when fail.
                      listenerList.remove(listenerPair);
                      if (listenerList.isEmpty()) {
                          // Remove the device if its listener list is empty
                          sMetadataListeners.remove(device);
                      }
                  }
              }
              return ret;
          }
      }
  
      /**
       * Unregister a {@link #OnMetadataChangedListener} from a registered {@link BluetoothDevice}.
       * Unregistration can be done when Bluetooth is either ON or OFF.
       * {@link #addOnMetadataChangedListener(OnMetadataChangedListener, BluetoothDevice, Executor)}
       * must be called before unregisteration.
       *
       * @param device {@link BluetoothDevice} that will be unregistered. It
       * should not be null or {@link NullPointerException} will be triggered.
       * @param listener {@link OnMetadataChangedListener} that will be unregistered. It
       * should not be null or {@link NullPointerException} will be triggered.
       * @return true on success, false on error
       * @throws NullPointerException If {@code listener} or {@code device} is null.
       * @throws IllegalArgumentException If {@code device} has not been registered before.
       * @hide
       */
      @SystemApi
      @RequiresPermission(Manifest.permission.BLUETOOTH_PRIVILEGED)
      public boolean removeOnMetadataChangedListener(@NonNull BluetoothDevice device,
              @NonNull OnMetadataChangedListener listener) {
          if (DBG) Log.d(TAG, "removeOnMetadataChangedListener()");
          if (device == null) {
              throw new NullPointerException("device is null");
          }
          if (listener == null) {
              throw new NullPointerException("listener is null");
          }
  
          synchronized (sMetadataListeners) {
              if (!sMetadataListeners.containsKey(device)) {
                  throw new IllegalArgumentException("device was not registered");
              }
              // Remove issued listener from the registered device
              sMetadataListeners.get(device).removeIf((pair) -> (pair.first.equals(listener)));
  
              if (sMetadataListeners.get(device).isEmpty()) {
                  // Unregister to Bluetooth service if all listeners are removed from
                  // the registered device
                  sMetadataListeners.remove(device);
                  final IBluetooth service = mService;
                  if (service == null) {
                      // Bluetooth is OFF, do nothing to Bluetooth service.
                      return true;
                  }
                  try {
                      return service.unregisterMetadataListener(device);
                  } catch (RemoteException e) {
                      Log.e(TAG, "unregisterMetadataListener fail", e);
                      return false;
                  }
              }
          }
          return true;
      }
  
      /**
       * This interface is used to implement {@link BluetoothAdapter} metadata listener.
       * @hide
       */
      @SystemApi
      public interface OnMetadataChangedListener {
          /**
           * Callback triggered if the metadata of {@link BluetoothDevice} registered in
           * {@link #addOnMetadataChangedListener}.
           *
           * @param device changed {@link BluetoothDevice}.
           * @param key changed metadata key, one of BluetoothDevice.METADATA_*.
           * @param value the new value of metadata as byte array.
           */
          void onMetadataChanged(@NonNull BluetoothDevice device, int key,
                  @Nullable byte[] value);
      }
  }
  