content: /*
   * Copyright (C) 2011 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.android.nfc_extras;
  
  import java.util.HashMap;
  
  import android.content.Context;
  import android.nfc.INfcAdapterExtras;
  import android.nfc.NfcAdapter;
  import android.os.RemoteException;
  import android.util.Log;
  
  /**
   * Provides additional methods on an {@link NfcAdapter} for Card Emulation
   * and management of {@link NfcExecutionEnvironment}'s.
   *
   * There is a 1-1 relationship between an {@link NfcAdapterExtras} object and
   * a {@link NfcAdapter} object.
   */
  public final class NfcAdapterExtras {
      private static final String TAG = "NfcAdapterExtras";
  
      /**
       * Broadcast Action: an RF field ON has been detected.
       *
       * <p class="note">This is an unreliable signal, and will be removed.
       * <p class="note">
       * Requires the {@link android.Manifest.permission#WRITE_SECURE_SETTINGS} permission
       * to receive.
       */
      public static final String ACTION_RF_FIELD_ON_DETECTED =
              "com.android.nfc_extras.action.RF_FIELD_ON_DETECTED";
  
      /**
       * Broadcast Action: an RF field OFF has been detected.
       *
       * <p class="note">This is an unreliable signal, and will be removed.
       * <p class="note">
       * Requires the {@link android.Manifest.permission#WRITE_SECURE_SETTINGS} permission
       * to receive.
       */
      public static final String ACTION_RF_FIELD_OFF_DETECTED =
              "com.android.nfc_extras.action.RF_FIELD_OFF_DETECTED";
  
      // protected by NfcAdapterExtras.class, and final after first construction,
      // except for attemptDeadServiceRecovery() when NFC crashes - we accept a
      // best effort recovery
      private static INfcAdapterExtras sService;
      private static final CardEmulationRoute ROUTE_OFF =
              new CardEmulationRoute(CardEmulationRoute.ROUTE_OFF, null);
  
      // contents protected by NfcAdapterExtras.class
      private static final HashMap<NfcAdapter, NfcAdapterExtras> sNfcExtras = new HashMap();
  
      private final NfcExecutionEnvironment mEmbeddedEe;
      private final CardEmulationRoute mRouteOnWhenScreenOn;
  
      private final NfcAdapter mAdapter;
      final String mPackageName;
  
      /** get service handles */
      private static void initService(NfcAdapter adapter) {
          final INfcAdapterExtras service = adapter.getNfcAdapterExtrasInterface();
          if (service != null) {
              // Leave stale rather than receive a null value.
              sService = service;
          }
      }
  
      /**
       * Get the {@link NfcAdapterExtras} for the given {@link NfcAdapter}.
       *
       * <p class="note">
       * Requires the {@link android.Manifest.permission#WRITE_SECURE_SETTINGS} permission.
       *
       * @param adapter a {@link NfcAdapter}, must not be null
       * @return the {@link NfcAdapterExtras} object for the given {@link NfcAdapter}
       */
      public static NfcAdapterExtras get(NfcAdapter adapter) {
          Context context = adapter.getContext();
          if (context == null) {
              throw new UnsupportedOperationException(
                      "You must pass a context to your NfcAdapter to use the NFC extras APIs");
          }
  
          synchronized (NfcAdapterExtras.class) {
              if (sService == null) {
                  initService(adapter);
              }
              NfcAdapterExtras extras = sNfcExtras.get(adapter);
              if (extras == null) {
                  extras = new NfcAdapterExtras(adapter);
                  sNfcExtras.put(adapter,  extras);
              }
              return extras;
          }
      }
  
      private NfcAdapterExtras(NfcAdapter adapter) {
          mAdapter = adapter;
          mPackageName = adapter.getContext().getPackageName();
          mEmbeddedEe = new NfcExecutionEnvironment(this);
          mRouteOnWhenScreenOn = new CardEmulationRoute(CardEmulationRoute.ROUTE_ON_WHEN_SCREEN_ON,
                  mEmbeddedEe);
      }
  
      /**
       * Immutable data class that describes a card emulation route.
       */
      public final static class CardEmulationRoute {
          /**
           * Card Emulation is turned off on this NfcAdapter.
           * <p>This is the default routing state after boot.
           */
          public static final int ROUTE_OFF = 1;
  
          /**
           * Card Emulation is routed to {@link #nfcEe} only when the screen is on,
           * otherwise it is turned off.
           */
          public static final int ROUTE_ON_WHEN_SCREEN_ON = 2;
  
          /**
           * A route such as {@link #ROUTE_OFF} or {@link #ROUTE_ON_WHEN_SCREEN_ON}.
           */
          public final int route;
  
          /**
           * The {@link NFcExecutionEnvironment} that is Card Emulation is routed to.
           * <p>null if {@link #route} is {@link #ROUTE_OFF}, otherwise not null.
           */
          public final NfcExecutionEnvironment nfcEe;
  
          public CardEmulationRoute(int route, NfcExecutionEnvironment nfcEe) {
              if (route == ROUTE_OFF && nfcEe != null) {
                  throw new IllegalArgumentException("must not specifiy a NFC-EE with ROUTE_OFF");
              } else if (route != ROUTE_OFF && nfcEe == null) {
                  throw new IllegalArgumentException("must specifiy a NFC-EE for this route");
              }
              this.route = route;
              this.nfcEe = nfcEe;
          }
      }
  
      /**
       * NFC service dead - attempt best effort recovery
       */
      void attemptDeadServiceRecovery(Exception e) {
          Log.e(TAG, "NFC Adapter Extras dead - attempting to recover");
          mAdapter.attemptDeadServiceRecovery(e);
          initService(mAdapter);
      }
  
      INfcAdapterExtras getService() {
          return sService;
      }
  
      /**
       * Get the routing state of this NFC EE.
       *
       * <p class="note">
       * Requires the {@link android.Manifest.permission#WRITE_SECURE_SETTINGS} permission.
       */
      public CardEmulationRoute getCardEmulationRoute() {
          try {
              int route = sService.getCardEmulationRoute(mPackageName);
              return route == CardEmulationRoute.ROUTE_OFF ?
                      ROUTE_OFF :
                      mRouteOnWhenScreenOn;
          } catch (RemoteException e) {
              attemptDeadServiceRecovery(e);
              return ROUTE_OFF;
          }
      }
  
      /**
       * Set the routing state of this NFC EE.
       *
       * <p>This routing state is not persisted across reboot.
       *
       * <p class="note">
       * Requires the {@link android.Manifest.permission#WRITE_SECURE_SETTINGS} permission.
       *
       * @param route a {@link CardEmulationRoute}
       */
      public void setCardEmulationRoute(CardEmulationRoute route) {
          try {
              sService.setCardEmulationRoute(mPackageName, route.route);
          } catch (RemoteException e) {
              attemptDeadServiceRecovery(e);
          }
      }
  
      /**
       * Get the {@link NfcExecutionEnvironment} that is embedded with the
       * {@link NfcAdapter}.
       *
       * <p class="note">
       * Requires the {@link android.Manifest.permission#WRITE_SECURE_SETTINGS} permission.
       *
       * @return a {@link NfcExecutionEnvironment}, or null if there is no embedded NFC-EE
       */
      public NfcExecutionEnvironment getEmbeddedExecutionEnvironment() {
          return mEmbeddedEe;
      }
  
      /**
       * Authenticate the client application.
       *
       * Some implementations of NFC Adapter Extras may require applications
       * to authenticate with a token, before using other methods.
       *
       * @param token a implementation specific token
       * @throws java.lang.SecurityException if authentication failed
       */
      public void authenticate(byte[] token) {
          try {
              sService.authenticate(mPackageName, token);
          } catch (RemoteException e) {
              attemptDeadServiceRecovery(e);
          }
      }
  
      /**
       * Returns the name of this adapter's driver.
       *
       * <p>Different NFC adapters may use different drivers.  This value is
       * informational and should not be parsed.
       *
       * @return the driver name, or empty string if unknown
       */
      public String getDriverName() {
          try {
              return sService.getDriverName(mPackageName);
          } catch (RemoteException e) {
              attemptDeadServiceRecovery(e);
              return "";
          }
      }
  }
  