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 android.hardware.usb;
  
  import android.annotation.NonNull;
  import android.annotation.Nullable;
  import android.app.ActivityThread;
  import android.os.Parcel;
  import android.os.Parcelable;
  import android.os.RemoteException;
  
  import com.android.internal.util.Preconditions;
  
  /**
   * A class representing a USB accessory, which is an external hardware component
   * that communicates with an android application over USB.
   * The accessory is the USB host and android the device side of the USB connection.
   *
   * <p>When the accessory connects, it reports its manufacturer and model names,
   * the version of the accessory, and a user visible description of the accessory to the device.
   * The manufacturer, model and version strings are used by the USB Manager to choose
   * an appropriate application for the accessory.
   * The accessory may optionally provide a unique serial number
   * and a URL to for the accessory's website to the device as well.
   *
   * <p>An instance of this class is sent to the application via the
   * {@link UsbManager#ACTION_USB_ACCESSORY_ATTACHED} Intent.
   * The application can then call {@link UsbManager#openAccessory} to open a file descriptor
   * for reading and writing data to and from the accessory.
   *
   * <div class="special reference">
   * <h3>Developer Guides</h3>
   * <p>For more information about communicating with USB hardware, read the
   * <a href="{@docRoot}guide/topics/usb/index.html">USB</a> developer guide.</p>
   * </div>
   */
  public class UsbAccessory implements Parcelable {
  
      private static final String TAG = "UsbAccessory";
  
      private final @NonNull String mManufacturer;
      private final @NonNull String mModel;
      private final @Nullable String mDescription;
      private final @Nullable String mVersion;
      private final @Nullable String mUri;
      private final @NonNull IUsbSerialReader mSerialNumberReader;
  
      /** @hide */
      public static final int MANUFACTURER_STRING = 0;
      /** @hide */
      public static final int MODEL_STRING = 1;
      /** @hide */
      public static final int DESCRIPTION_STRING = 2;
      /** @hide */
      public static final int VERSION_STRING = 3;
      /** @hide */
      public static final int URI_STRING = 4;
      /** @hide */
      public static final int SERIAL_STRING = 5;
  
      /**
       * UsbAccessory should only be instantiated by UsbService implementation
       * @hide
       */
      public UsbAccessory(@NonNull String manufacturer, @NonNull String model,
              @Nullable String description, @Nullable String version, @Nullable String uri,
              @NonNull IUsbSerialReader serialNumberReader) {
          mManufacturer = Preconditions.checkNotNull(manufacturer);
          mModel = Preconditions.checkNotNull(model);
          mDescription = description;
          mVersion = version;
          mUri = uri;
          mSerialNumberReader = serialNumberReader;
  
          // Make sure the binder belongs to the system
          if (ActivityThread.isSystem()) {
              Preconditions.checkArgument(mSerialNumberReader instanceof IUsbSerialReader.Stub);
          }
      }
  
      /**
       * DO NOT USE. Only for backwards compatibility with
       * {@link com.android.future.usb.UsbAccessory}.
       *
       * @hide
       * @deprecated use {@link UsbAccessory#UsbAccessory(String, String, String, String, String,
       *             IUsbSerialReader) instead}
       */
      @Deprecated
      public UsbAccessory(@NonNull String manufacturer, @NonNull String model,
              @Nullable String description, @Nullable String version, @Nullable String uri,
              @Nullable String serialNumber) {
          this(manufacturer, model, description, version, uri, new IUsbSerialReader.Stub() {
              @Override
              public String getSerial(String packageName) {
                  return serialNumber;
              }
          });
      }
  
      /**
       * Returns the manufacturer name of the accessory.
       *
       * @return the accessory manufacturer
       */
      public @NonNull String getManufacturer() {
          return mManufacturer;
      }
  
      /**
       * Returns the model name of the accessory.
       *
       * @return the accessory model
       */
      public @NonNull String getModel() {
          return mModel;
      }
  
      /**
       * Returns a user visible description of the accessory.
       *
       * @return the accessory description, or {@code null} if not set
       */
      public @Nullable String getDescription() {
          return mDescription;
      }
  
      /**
       * Returns the version of the accessory.
       *
       * @return the accessory version, or {@code null} if not set
       */
      public @Nullable String getVersion() {
          return mVersion;
      }
  
      /**
       * Returns the URI for the accessory.
       * This is an optional URI that might show information about the accessory
       * or provide the option to download an application for the accessory
       *
       * @return the accessory URI, or {@code null} if not set
       */
      public @Nullable String getUri() {
          return mUri;
      }
  
      /**
       * Returns the unique serial number for the accessory.
       * This is an optional serial number that can be used to differentiate
       * between individual accessories of the same model and manufacturer
       *
       * @return the unique serial number, or {@code null} if not set
       *
       * @throws SecurityException if the app targets SDK >= {@value android.os.Build.VERSION_CODES#Q}
       *                           and the app does not have permission to read from the accessory.
       */
      public @Nullable String getSerial() {
          try {
              return mSerialNumberReader.getSerial(ActivityThread.currentPackageName());
          } catch (RemoteException e) {
              e.rethrowFromSystemServer();
              return null;
          }
      }
  
      private static boolean compare(String s1, String s2) {
          if (s1 == null) return (s2 == null);
          return s1.equals(s2);
      }
  
      @Override
      public boolean equals(Object obj) {
          if (obj instanceof UsbAccessory) {
              UsbAccessory accessory = (UsbAccessory)obj;
              return (compare(mManufacturer, accessory.getManufacturer()) &&
                      compare(mModel, accessory.getModel()) &&
                      compare(mDescription, accessory.getDescription()) &&
                      compare(mVersion, accessory.getVersion()) &&
                      compare(mUri, accessory.getUri()) &&
                      compare(getSerial(), accessory.getSerial()));
          }
          return false;
      }
  
      @Override
      public int hashCode() {
          return mManufacturer.hashCode() ^ mModel.hashCode() ^
                  (mDescription == null ? 0 : mDescription.hashCode()) ^
                  (mVersion == null ? 0 : mVersion.hashCode()) ^
                  (mUri == null ? 0 : mUri.hashCode());
      }
  
      @Override
      public String toString() {
          return "UsbAccessory[mManufacturer=" + mManufacturer +
                              ", mModel=" + mModel +
                              ", mDescription=" + mDescription +
                              ", mVersion=" + mVersion +
                              ", mUri=" + mUri +
                              ", mSerialNumberReader=" + mSerialNumberReader + "]";
      }
  
      public static final @android.annotation.NonNull Parcelable.Creator<UsbAccessory> CREATOR =
          new Parcelable.Creator<UsbAccessory>() {
          public UsbAccessory createFromParcel(Parcel in) {
              String manufacturer = in.readString();
              String model = in.readString();
              String description = in.readString();
              String version = in.readString();
              String uri = in.readString();
              IUsbSerialReader serialNumberReader = IUsbSerialReader.Stub.asInterface(
                      in.readStrongBinder());
  
              return new UsbAccessory(manufacturer, model, description, version, uri,
                      serialNumberReader);
          }
  
          public UsbAccessory[] newArray(int size) {
              return new UsbAccessory[size];
          }
      };
  
      public int describeContents() {
          return 0;
      }
  
      public void writeToParcel(Parcel parcel, int flags) {
          parcel.writeString(mManufacturer);
          parcel.writeString(mModel);
          parcel.writeString(mDescription);
          parcel.writeString(mVersion);
          parcel.writeString(mUri);
          parcel.writeStrongBinder(mSerialNumberReader.asBinder());
     }
  }
  