2 files changed, 317 insertions(+), 2 deletions(-)

M src/main/java/org/safcephfs/CephFSDocumentsProvider.java
A src/main/java/org/safcephfs/MetadataReader.java

@@ 11,6 11,7 @@ import android.os.HandlerThread;
 import android.os.Looper;
 import android.os.Message;
 import android.os.ParcelFileDescriptor;
+import android.os.ParcelFileDescriptor.AutoCloseInputStream;
 import android.os.Process;
 import android.os.storage.StorageManager;
 import android.os.StrictMode;


@@ 339,11 340,19 @@ public class CephFSDocumentsProvider extends DocumentsProvider {
 				row.add(Document.COLUMN_FLAGS, Document.FLAG_DIR_SUPPORTS_CREATE);
 			}
 		} else if (cs.isFile()) {
-			row.add(Document.COLUMN_MIME_TYPE, getMime(filename));
+			String mimeType = getMime(filename);
+			row.add(Document.COLUMN_MIME_TYPE, mimeType);
+			int flags = 0;
+			if (MetadataReader.isSupportedMimeType(mimeType) &&
+					(!checkPermissions ||
+					(getPerm(cs) & PERM_READABLE) == PERM_READABLE)) {
+				flags |= Document.FLAG_SUPPORTS_METADATA;
+			}
 			if (!checkPermissions ||
 					(getPerm(cs) & PERM_WRITEABLE) == PERM_WRITEABLE) {
-				row.add(Document.COLUMN_FLAGS, Document.FLAG_SUPPORTS_WRITE);
+				flags |= Document.FLAG_SUPPORTS_WRITE;
 			}
+			row.add(Document.COLUMN_FLAGS, flags);
 		} else if (cs.isSymlink()) {
 			row.add(Document.COLUMN_MIME_TYPE, "inode/symlink");
 		} else {


@@ 385,6 394,27 @@ public class CephFSDocumentsProvider extends DocumentsProvider {
 		return result;
 	}
 
+	public Bundle getDocumentMetadata(String documentId)
+			throws FileNotFoundException {
+		Log.v(APP_NAME, "getDocumentMetadata " + documentId);
+		String mimeType = getDocumentType(documentId);
+		if (!MetadataReader.isSupportedMimeType(mimeType)) {
+			return null;
+		}
+
+		ParcelFileDescriptor fd = openDocument(documentId, "r", null);
+		AutoCloseInputStream stream = new AutoCloseInputStream(fd);
+
+		Bundle metadata = new Bundle();
+		try {
+			MetadataReader.getMetadata(metadata, stream, mimeType, null);
+		} catch (IOException e) {
+			Log.e(APP_NAME, "getMetadata: ", e);
+			return null;
+		}
+		return metadata;
+	}
+
 	public Cursor queryRoots(String[] projection)
 			throws FileNotFoundException {
 		MatrixCursor result = new MatrixCursor(projection != null ? projection : DEFAULT_ROOT_PROJECTION);

@@ 0,0 1,285 @@
+/*
+ * 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.
+ */
+
+/*
+ * Changed to remove Nullable annotation and make it under org.safcephfs
+ * namespace.
+ */
+
+package org.safcephfs;
+
+import android.media.ExifInterface;
+import android.provider.DocumentsContract;
+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,
+            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, 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;
+    }
+}