content: /*
   * Copyright (C) 2017 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.provider;
  
  import android.annotation.Nullable;
  import android.media.ExifInterface;
  import android.os.Bundle;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  /**
   * Class providing support for extracting metadata from a file as a
   * {@link Bundle} suitable for use with {@link DocumentsContract#getDocumentMetadata}.
   * <p>Currently only EXIF data is supported.
   * <p>TODO: Add support for common video and audio types, as well as PDF files.
   * {@hide}
   */
  public final class MetadataReader {
  
      private MetadataReader() {}
  
      private static final String[] DEFAULT_EXIF_TAGS = {
              ExifInterface.TAG_APERTURE,
              ExifInterface.TAG_COPYRIGHT,
              ExifInterface.TAG_DATETIME,
              ExifInterface.TAG_EXPOSURE_TIME,
              ExifInterface.TAG_FOCAL_LENGTH,
              ExifInterface.TAG_F_NUMBER,
              ExifInterface.TAG_GPS_LATITUDE,
              ExifInterface.TAG_GPS_LATITUDE_REF,
              ExifInterface.TAG_GPS_LONGITUDE,
              ExifInterface.TAG_GPS_LONGITUDE_REF,
              ExifInterface.TAG_IMAGE_LENGTH,
              ExifInterface.TAG_IMAGE_WIDTH,
              ExifInterface.TAG_ISO_SPEED_RATINGS,
              ExifInterface.TAG_MAKE,
              ExifInterface.TAG_MODEL,
              ExifInterface.TAG_ORIENTATION,
              ExifInterface.TAG_SHUTTER_SPEED_VALUE,
      };
  
      private static final int TYPE_INT = 0;
      private static final int TYPE_DOUBLE = 1;
      private static final int TYPE_STRING = 2;
  
      private static final Map<String, Integer> TYPE_MAPPING = new HashMap<>();
      static {
          // TODO: Move this over to ExifInterface.java
          // Since each ExifInterface item has a type, and there's currently no way to get the type
          // from the tag, here we identify the tag to the type so that we can call the correct
          // ExifInterface method
          TYPE_MAPPING.put(ExifInterface.TAG_ARTIST, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_BITS_PER_SAMPLE, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_COMPRESSION, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_COPYRIGHT, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_DATETIME, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_IMAGE_DESCRIPTION, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_IMAGE_LENGTH, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_IMAGE_WIDTH, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_JPEG_INTERCHANGE_FORMAT, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_JPEG_INTERCHANGE_FORMAT_LENGTH, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_MAKE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_MODEL, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_ORIENTATION, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_PHOTOMETRIC_INTERPRETATION, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_PLANAR_CONFIGURATION, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_PRIMARY_CHROMATICITIES, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_REFERENCE_BLACK_WHITE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_RESOLUTION_UNIT, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_ROWS_PER_STRIP, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_SAMPLES_PER_PIXEL, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_SOFTWARE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_STRIP_BYTE_COUNTS, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_STRIP_OFFSETS, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_TRANSFER_FUNCTION, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_WHITE_POINT, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_X_RESOLUTION, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_Y_CB_CR_COEFFICIENTS, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_Y_CB_CR_POSITIONING, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_Y_CB_CR_SUB_SAMPLING, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_Y_RESOLUTION, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_APERTURE_VALUE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_BRIGHTNESS_VALUE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_CFA_PATTERN, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_COLOR_SPACE, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_COMPONENTS_CONFIGURATION, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_COMPRESSED_BITS_PER_PIXEL, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_CONTRAST, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_CUSTOM_RENDERED, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_DATETIME_DIGITIZED, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_DATETIME_ORIGINAL, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_DEVICE_SETTING_DESCRIPTION, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_DIGITAL_ZOOM_RATIO, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_EXIF_VERSION, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_EXPOSURE_BIAS_VALUE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_EXPOSURE_INDEX, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_EXPOSURE_MODE, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_EXPOSURE_PROGRAM, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_EXPOSURE_TIME, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_F_NUMBER, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_FILE_SOURCE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_FLASH, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_FLASH_ENERGY, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_FLASHPIX_VERSION, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_FOCAL_LENGTH, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_FOCAL_LENGTH_IN_35MM_FILM, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_FOCAL_PLANE_RESOLUTION_UNIT, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_FOCAL_PLANE_X_RESOLUTION, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_FOCAL_PLANE_Y_RESOLUTION, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_GAIN_CONTROL, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_ISO_SPEED_RATINGS, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_IMAGE_UNIQUE_ID, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_LIGHT_SOURCE, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_MAKER_NOTE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_MAX_APERTURE_VALUE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_METERING_MODE, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_NEW_SUBFILE_TYPE, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_OECF, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_PIXEL_X_DIMENSION, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_PIXEL_Y_DIMENSION, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_RELATED_SOUND_FILE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_SATURATION, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_SCENE_CAPTURE_TYPE, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_SCENE_TYPE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_SENSING_METHOD, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_SHARPNESS, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_SHUTTER_SPEED_VALUE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_SPATIAL_FREQUENCY_RESPONSE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_SPECTRAL_SENSITIVITY, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_SUBFILE_TYPE, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_SUBSEC_TIME, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_SUBSEC_TIME_DIGITIZED, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_SUBSEC_TIME_ORIGINAL, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_SUBJECT_AREA, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_SUBJECT_DISTANCE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_SUBJECT_DISTANCE_RANGE, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_SUBJECT_LOCATION, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_USER_COMMENT, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_WHITE_BALANCE, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_ALTITUDE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_ALTITUDE_REF, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_AREA_INFORMATION, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DOP, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DATESTAMP, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DEST_BEARING, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DEST_BEARING_REF, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DEST_DISTANCE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DEST_DISTANCE_REF, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DEST_LATITUDE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DEST_LATITUDE_REF, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DEST_LONGITUDE, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DEST_LONGITUDE_REF, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_DIFFERENTIAL, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_IMG_DIRECTION, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_IMG_DIRECTION_REF, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_LATITUDE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_LATITUDE_REF, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_LONGITUDE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_LONGITUDE_REF, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_MAP_DATUM, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_MEASURE_MODE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_PROCESSING_METHOD, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_SATELLITES, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_SPEED, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_SPEED_REF, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_STATUS, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_TIMESTAMP, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_TRACK, TYPE_DOUBLE);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_TRACK_REF, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_GPS_VERSION_ID, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_INTEROPERABILITY_INDEX, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_THUMBNAIL_IMAGE_LENGTH, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_THUMBNAIL_IMAGE_WIDTH, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_DNG_VERSION, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_DEFAULT_CROP_SIZE, TYPE_INT);
          //I don't know how to represent this. Type is unknown
          //TYPE_MAPPING.put(ExifInterface.TAG_ORF_THUMBNAIL_IMAGE, TYPE_STRING);
          TYPE_MAPPING.put(ExifInterface.TAG_ORF_PREVIEW_IMAGE_START, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_ORF_PREVIEW_IMAGE_LENGTH, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_ORF_ASPECT_FRAME, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_RW2_SENSOR_BOTTOM_BORDER, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_RW2_SENSOR_LEFT_BORDER, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_RW2_SENSOR_RIGHT_BORDER, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_RW2_SENSOR_TOP_BORDER, TYPE_INT);
          TYPE_MAPPING.put(ExifInterface.TAG_RW2_ISO, TYPE_INT);
      }
      private static final String JPG_MIME_TYPE = "image/jpg";
      private static final String JPEG_MIME_TYPE = "image/jpeg";
  
  
      /**
       * Returns true if caller can generally expect to get metadata results
       * for the supplied mimetype.
       */
      public static boolean isSupportedMimeType(String mimeType) {
          return JPG_MIME_TYPE.equals(mimeType) || JPEG_MIME_TYPE.equals(mimeType);
      }
  
      /**
       * Generic metadata retrieval method that can retrieve any available metadata from a given doc
       * Currently only functions for exifdata
       *
       * @param metadata the bundle to which we add any relevant metadata
       * @param stream InputStream containing a file
       * @param mimeType type of the given file
       * @param tags a variable amount of keys to differentiate which tags the user wants
       *             if null, returns a default set of data. See {@link DEFAULT_EXIF_TAGS}.
       * @throws IOException when the file doesn't exist
       */
      public static void getMetadata(Bundle metadata, InputStream stream, String mimeType,
              @Nullable String[] tags) throws IOException {
          List<String> metadataTypes = new ArrayList<>();
          if (isSupportedMimeType(mimeType)) {
              Bundle exifData = getExifData(stream, tags);
              if (exifData.size() > 0) {
                  metadata.putBundle(DocumentsContract.METADATA_EXIF, exifData);
                  metadataTypes.add(DocumentsContract.METADATA_EXIF);
              }
          }
          metadata.putStringArray(DocumentsContract.METADATA_TYPES,
                  metadataTypes.toArray(new String[metadataTypes.size()]));
          // TODO: Add support for PDF and Video metadata
          // TODO: Broaden image support to all images
      }
  
      /**
       * Helper method that is called if getMetadata is called for an image mimeType.
       *
       * @param stream the input stream from which to extra data.
       * @param tags a list of ExifInterface tags that are used to retrieve data.
       *             if null, returns a default set of data. See {@link DEFAULT_EXIF_TAGS}.
       */
      private static Bundle getExifData(InputStream stream, @Nullable String[] tags)
              throws IOException {
          if (tags == null) {
              tags = DEFAULT_EXIF_TAGS;
          }
  
          ExifInterface exifInterface = new ExifInterface(stream);
          Bundle exif = new Bundle();
          for (String tag : tags) {
              if (TYPE_MAPPING.get(tag).equals(TYPE_INT)) {
                  int data = exifInterface.getAttributeInt(tag, Integer.MIN_VALUE);
                  if (data != Integer.MIN_VALUE) {
                      exif.putInt(tag, data);
                  }
              } else if (TYPE_MAPPING.get(tag).equals(TYPE_DOUBLE)) {
                  double data = exifInterface.getAttributeDouble(tag, Double.MIN_VALUE);
                  if (data != Double.MIN_VALUE) {
                      exif.putDouble(tag, data);
                  }
              } else if (TYPE_MAPPING.get(tag).equals(TYPE_STRING)) {
                  String data = exifInterface.getAttribute(tag);
                  if (data != null) {
                      exif.putString(tag, data);
                  }
              }
          }
          return exif;
      }
  }
  