content: /*
   * Copyright (C) 2015 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.nfc.cardemulation;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  
  import org.xmlpull.v1.XmlPullParser;
  import org.xmlpull.v1.XmlPullParserException;
  import org.xmlpull.v1.XmlSerializer;
  
  import android.annotation.UnsupportedAppUsage;
  import android.os.Parcel;
  import android.os.Parcelable;
  import android.util.Log;
  
  /**
   * The AidGroup class represents a group of Application Identifiers (AIDs).
   *
   * <p>The format of AIDs is defined in the ISO/IEC 7816-4 specification. This class
   * requires the AIDs to be input as a hexadecimal string, with an even amount of
   * hexadecimal characters, e.g. "F014811481".
   *
   * @hide
   */
  public final class AidGroup implements Parcelable {
      /**
       * The maximum number of AIDs that can be present in any one group.
       */
      public static final int MAX_NUM_AIDS = 256;
  
      static final String TAG = "AidGroup";
  
      @UnsupportedAppUsage
      final List<String> aids;
      @UnsupportedAppUsage
      final String category;
      @UnsupportedAppUsage
      final String description;
  
      /**
       * Creates a new AidGroup object.
       *
       * @param aids The list of AIDs present in the group
       * @param category The category of this group, e.g. {@link CardEmulation#CATEGORY_PAYMENT}
       */
      public AidGroup(List<String> aids, String category) {
          if (aids == null || aids.size() == 0) {
              throw new IllegalArgumentException("No AIDS in AID group.");
          }
          if (aids.size() > MAX_NUM_AIDS) {
              throw new IllegalArgumentException("Too many AIDs in AID group.");
          }
          for (String aid : aids) {
              if (!CardEmulation.isValidAid(aid)) {
                  throw new IllegalArgumentException("AID " + aid + " is not a valid AID.");
              }
          }
          if (isValidCategory(category)) {
              this.category = category;
          } else {
              this.category = CardEmulation.CATEGORY_OTHER;
          }
          this.aids = new ArrayList<String>(aids.size());
          for (String aid : aids) {
              this.aids.add(aid.toUpperCase());
          }
          this.description = null;
      }
  
      @UnsupportedAppUsage
      AidGroup(String category, String description) {
          this.aids = new ArrayList<String>();
          this.category = category;
          this.description = description;
      }
  
      /**
       * @return the category of this AID group
       */
      @UnsupportedAppUsage
      public String getCategory() {
          return category;
      }
  
      /**
       * @return the list of AIDs in this group
       */
      @UnsupportedAppUsage
      public List<String> getAids() {
          return aids;
      }
  
      @Override
      public String toString() {
          StringBuilder out = new StringBuilder("Category: " + category +
                    ", AIDs:");
          for (String aid : aids) {
              out.append(aid);
              out.append(", ");
          }
          return out.toString();
      }
  
      @Override
      public int describeContents() {
          return 0;
      }
  
      @Override
      public void writeToParcel(Parcel dest, int flags) {
          dest.writeString(category);
          dest.writeInt(aids.size());
          if (aids.size() > 0) {
              dest.writeStringList(aids);
          }
      }
  
      @UnsupportedAppUsage
      public static final @android.annotation.NonNull Parcelable.Creator<AidGroup> CREATOR =
              new Parcelable.Creator<AidGroup>() {
  
          @Override
          public AidGroup createFromParcel(Parcel source) {
              String category = source.readString();
              int listSize = source.readInt();
              ArrayList<String> aidList = new ArrayList<String>();
              if (listSize > 0) {
                  source.readStringList(aidList);
              }
              return new AidGroup(aidList, category);
          }
  
          @Override
          public AidGroup[] newArray(int size) {
              return new AidGroup[size];
          }
      };
  
      @UnsupportedAppUsage
      static public AidGroup createFromXml(XmlPullParser parser) throws XmlPullParserException, IOException {
          String category = null;
          ArrayList<String> aids = new ArrayList<String>();
          AidGroup group = null;
          boolean inGroup = false;
  
          int eventType = parser.getEventType();
          int minDepth = parser.getDepth();
          while (eventType != XmlPullParser.END_DOCUMENT && parser.getDepth() >= minDepth) {
              String tagName = parser.getName();
              if (eventType == XmlPullParser.START_TAG) {
                  if (tagName.equals("aid")) {
                      if (inGroup) {
                          String aid = parser.getAttributeValue(null, "value");
                          if (aid != null) {
                              aids.add(aid.toUpperCase());
                          }
                      } else {
                          Log.d(TAG, "Ignoring <aid> tag while not in group");
                      }
                  } else if (tagName.equals("aid-group")) {
                      category = parser.getAttributeValue(null, "category");
                      if (category == null) {
                          Log.e(TAG, "<aid-group> tag without valid category");
                          return null;
                      }
                      inGroup = true;
                  } else {
                      Log.d(TAG, "Ignoring unexpected tag: " + tagName);
                  }
              } else if (eventType == XmlPullParser.END_TAG) {
                  if (tagName.equals("aid-group") && inGroup && aids.size() > 0) {
                      group = new AidGroup(aids, category);
                      break;
                  }
              }
              eventType = parser.next();
          }
          return group;
      }
  
      @UnsupportedAppUsage
      public void writeAsXml(XmlSerializer out) throws IOException {
          out.startTag(null, "aid-group");
          out.attribute(null, "category", category);
          for (String aid : aids) {
              out.startTag(null, "aid");
              out.attribute(null, "value", aid);
              out.endTag(null, "aid");
          }
          out.endTag(null, "aid-group");
      }
  
      static boolean isValidCategory(String category) {
          return CardEmulation.CATEGORY_PAYMENT.equals(category) ||
                  CardEmulation.CATEGORY_OTHER.equals(category);
      }
  }
  