Clean ExifInterface. Prepare to make it public.
Change-Id: Ibff719d02f525c1e8583d1892737224a0cc42c37
diff --git a/media/java/android/media/ExifInterface.java b/media/java/android/media/ExifInterface.java
index aba40b3..2595532 100644
--- a/media/java/android/media/ExifInterface.java
+++ b/media/java/android/media/ExifInterface.java
@@ -16,8 +16,7 @@
package android.media;
-import android.util.Log;
-
+import java.io.IOException;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Date;
@@ -25,171 +24,103 @@
import java.util.Map;
/**
- * Wrapper for native Exif library
+ * This is a class for reading and writing Exif tags in a JPEG file.
* {@hide}
*/
public class ExifInterface {
- private static final String TAG = "ExifInterface";
- private String mFilename;
-
- // Constants used for the Orientation Exif tag.
- public static final int ORIENTATION_UNDEFINED = 0;
- public static final int ORIENTATION_NORMAL = 1;
-
- // Constants used for white balance
- public static final int WHITEBALANCE_AUTO = 0;
- public static final int WHITEBALANCE_MANUAL = 1;
-
- // left right reversed mirror
- public static final int ORIENTATION_FLIP_HORIZONTAL = 2;
- public static final int ORIENTATION_ROTATE_180 = 3;
-
- // upside down mirror
- public static final int ORIENTATION_FLIP_VERTICAL = 4;
-
- // flipped about top-left <--> bottom-right axis
- public static final int ORIENTATION_TRANSPOSE = 5;
-
- // rotate 90 cw to right it
- public static final int ORIENTATION_ROTATE_90 = 6;
-
- // flipped about top-right <--> bottom-left axis
- public static final int ORIENTATION_TRANSVERSE = 7;
-
- // rotate 270 to right it
- public static final int ORIENTATION_ROTATE_270 = 8;
// The Exif tag names
public static final String TAG_ORIENTATION = "Orientation";
-
public static final String TAG_DATETIME = "DateTime";
public static final String TAG_MAKE = "Make";
public static final String TAG_MODEL = "Model";
public static final String TAG_FLASH = "Flash";
public static final String TAG_IMAGE_WIDTH = "ImageWidth";
public static final String TAG_IMAGE_LENGTH = "ImageLength";
-
public static final String TAG_GPS_LATITUDE = "GPSLatitude";
public static final String TAG_GPS_LONGITUDE = "GPSLongitude";
-
public static final String TAG_GPS_LATITUDE_REF = "GPSLatitudeRef";
public static final String TAG_GPS_LONGITUDE_REF = "GPSLongitudeRef";
public static final String TAG_WHITE_BALANCE = "WhiteBalance";
- private boolean mSavedAttributes = false;
- private boolean mHasThumbnail = false;
- private HashMap<String, String> mCachedAttributes = null;
+ // Constants used for the Orientation Exif tag.
+ public static final int ORIENTATION_UNDEFINED = 0;
+ public static final int ORIENTATION_NORMAL = 1;
+ public static final int ORIENTATION_FLIP_HORIZONTAL = 2; // left right reversed mirror
+ public static final int ORIENTATION_ROTATE_180 = 3;
+ public static final int ORIENTATION_FLIP_VERTICAL = 4; // upside down mirror
+ public static final int ORIENTATION_TRANSPOSE = 5; // flipped about top-left <--> bottom-right axis
+ public static final int ORIENTATION_ROTATE_90 = 6; // rotate 90 cw to right it
+ public static final int ORIENTATION_TRANSVERSE = 7; // flipped about top-right <--> bottom-left axis
+ public static final int ORIENTATION_ROTATE_270 = 8; // rotate 270 to right it
+
+ // Constants used for white balance
+ public static final int WHITEBALANCE_AUTO = 0;
+ public static final int WHITEBALANCE_MANUAL = 1;
static {
System.loadLibrary("exif");
}
- private static ExifInterface sExifObj = null;
- /**
- * Since the underlying jhead native code is not thread-safe,
- * ExifInterface should use singleton interface instead of public
- * constructor.
- */
- private static synchronized ExifInterface instance() {
- if (sExifObj == null) {
- sExifObj = new ExifInterface();
- }
+ private String mFilename;
+ private HashMap<String, String> mAttributes;
+ private boolean mHasThumbnail = false;
- return sExifObj;
+ // Because the underlying implementation (jhead) uses static variables,
+ // there can only be one user at a time for the native functions (and
+ // they cannot keep state in the native code across function calls). We
+ // use sLock the serialize the accesses.
+ private static Object sLock = new Object();
+
+ /**
+ * Reads Exif tags from the specified JPEG file.
+ */
+ public ExifInterface(String filename) throws IOException {
+ mFilename = filename;
+ loadAttributes();
}
/**
- * The following 3 static methods are handy routines for atomic operation
- * of underlying jhead library. It retrieves EXIF data and then release
- * ExifInterface immediately.
+ * Returns the value of the specified tag or {@code null} if there
+ * is no such tag in the file.
+ *
+ * @param tag the name of the tag.
*/
- public static synchronized HashMap<String, String> loadExifData(String filename) {
- ExifInterface exif = instance();
- HashMap<String, String> exifData = null;
- if (exif != null) {
- exif.setFilename(filename);
- exifData = exif.getAttributes();
- }
- return exifData;
- }
-
- public static synchronized void saveExifData(String filename, HashMap<String, String> exifData) {
- ExifInterface exif = instance();
- if (exif != null) {
- exif.setFilename(filename);
- exif.saveAttributes(exifData);
- }
- }
-
- public static synchronized byte[] getExifThumbnail(String filename) {
- ExifInterface exif = instance();
- if (exif != null) {
- exif.setFilename(filename);
- return exif.getThumbnail();
- }
- return null;
- }
-
- public void setFilename(String filename) {
- if (mFilename == null || !mFilename.equals(filename)) {
- mFilename = filename;
- mCachedAttributes = null;
- }
+ public String getAttribute(String tag) {
+ return mAttributes.get(tag);
}
/**
- * Given a HashMap of Exif tags and associated values, an Exif section in
- * the JPG file is created and loaded with the tag data. saveAttributes()
- * is expensive because it involves copying all the JPG data from one file
- * to another and deleting the old file and renaming the other. It's best
- * to collect all the attributes to write and make a single call rather
- * than multiple calls for each attribute. You must call "commitChanges()"
- * at some point to commit the changes.
+ * Set the value of the specified tag.
+ *
+ * @param tag the name of the tag.
+ * @param value the value of the tag.
*/
- public void saveAttributes(HashMap<String, String> attributes) {
- // format of string passed to native C code:
- // "attrCnt attr1=valueLen value1attr2=value2Len value2..."
- // example:
- // "4 attrPtr ImageLength=4 1024Model=6 FooImageWidth=4 1280Make=3 FOO"
- StringBuilder sb = new StringBuilder();
- int size = attributes.size();
- if (attributes.containsKey("hasThumbnail")) {
- --size;
- }
- sb.append(size + " ");
- for (Map.Entry<String, String> iter : attributes.entrySet()) {
- String key = iter.getKey();
- if (key.equals("hasThumbnail")) {
- // this is a fake attribute not saved as an exif tag
- continue;
- }
- String val = iter.getValue();
- sb.append(key + "=");
- sb.append(val.length() + " ");
- sb.append(val);
- }
- String s = sb.toString();
- saveAttributesNative(mFilename, s);
- commitChangesNative(mFilename);
- mSavedAttributes = true;
+ public void setAttribute(String tag, String value) {
+ mAttributes.put(tag, value);
}
/**
- * Returns a HashMap loaded with the Exif attributes of the file. The key
- * is the standard tag name and the value is the tag's value: e.g.
- * Model -> Nikon. Numeric values are returned as strings.
+ * Initialize mAttributes with the attributes from the file mFilename.
+ *
+ * mAttributes is a HashMap which stores the Exif attributes of the file.
+ * The key is the standard tag name and the value is the tag's value: e.g.
+ * Model -> Nikon. Numeric values are stored as strings.
+ *
+ * This function also initialize mHasThumbnail to indicate whether the
+ * file has a thumbnail inside.
*/
- public HashMap<String, String> getAttributes() {
- if (mCachedAttributes != null) {
- return mCachedAttributes;
- }
+ private void loadAttributes() {
// format of string passed from native C code:
// "attrCnt attr1=valueLen value1attr2=value2Len value2..."
// example:
// "4 attrPtr ImageLength=4 1024Model=6 FooImageWidth=4 1280Make=3 FOO"
- mCachedAttributes = new HashMap<String, String>();
+ mAttributes = new HashMap<String, String>();
- String attrStr = getAttributesNative(mFilename);
+ String attrStr;
+ synchronized (sLock) {
+ attrStr = getAttributesNative(mFilename);
+ }
// get count
int ptr = attrStr.indexOf(' ');
@@ -215,17 +146,78 @@
if (attrName.equals("hasThumbnail")) {
mHasThumbnail = attrValue.equalsIgnoreCase("true");
} else {
- mCachedAttributes.put(attrName, attrValue);
+ mAttributes.put(attrName, attrValue);
}
}
- return mCachedAttributes;
}
/**
- * Given a numerical white balance value, return a
- * human-readable string describing it.
+ * Save the tag data into the JPEG file. This is expensive because it involves
+ * copying all the JPG data from one file to another and deleting the old file
+ * and renaming the other. It's best to use {@link setAttribute()} to set all
+ * attributes to write and make a single call rather than multiple calls for
+ * each attribute.
*/
- public static String whiteBalanceToString(int whitebalance) {
+ public void saveAttributes() throws IOException {
+ // format of string passed to native C code:
+ // "attrCnt attr1=valueLen value1attr2=value2Len value2..."
+ // example:
+ // "4 attrPtr ImageLength=4 1024Model=6 FooImageWidth=4 1280Make=3 FOO"
+ StringBuilder sb = new StringBuilder();
+ int size = mAttributes.size();
+ if (mAttributes.containsKey("hasThumbnail")) {
+ --size;
+ }
+ sb.append(size + " ");
+ for (Map.Entry<String, String> iter : mAttributes.entrySet()) {
+ String key = iter.getKey();
+ if (key.equals("hasThumbnail")) {
+ // this is a fake attribute not saved as an exif tag
+ continue;
+ }
+ String val = iter.getValue();
+ sb.append(key + "=");
+ sb.append(val.length() + " ");
+ sb.append(val);
+ }
+ String s = sb.toString();
+ synchronized (sLock) {
+ saveAttributesNative(mFilename, s);
+ commitChangesNative(mFilename);
+ }
+ }
+
+ /**
+ * Returns true if the JPEG file has a thumbnail.
+ */
+ public boolean hasThumbnail() {
+ return mHasThumbnail;
+ }
+
+ /**
+ * Returns the thumbnail inside the JPEG file, or {@code null} if there is no thumbnail.
+ */
+ public byte[] getThumbnail() {
+ synchronized (sLock) {
+ return getThumbnailNative(mFilename);
+ }
+ }
+
+ /**
+ * Returns a human-readable string describing the white balance value. Returns empty
+ * string if there is no white balance value or it is not recognized.
+ */
+ public String getWhiteBalanceString() {
+ String value = getAttribute(TAG_WHITE_BALANCE);
+ if (value == null) return "";
+
+ int whitebalance;
+ try {
+ whitebalance = Integer.parseInt(value);
+ } catch (NumberFormatException ex) {
+ return "";
+ }
+
switch (whitebalance) {
case WHITEBALANCE_AUTO:
return "Auto";
@@ -237,12 +229,21 @@
}
/**
- * Given a numerical orientation, return a human-readable string describing
- * the orientation.
+ * Returns a human-readable string describing the orientation value. Returns empty
+ * string if there is no orientation value or it it not recognized.
*/
- public static String orientationToString(int orientation) {
- // TODO: this function needs to be localized and use string resource ids
- // rather than strings
+ public String getOrientationString() {
+ // TODO: this function needs to be localized.
+ String value = getAttribute(TAG_ORIENTATION);
+ if (value == null) return "";
+
+ int orientation;
+ try {
+ orientation = Integer.parseInt(value);
+ } catch (NumberFormatException ex) {
+ return "";
+ }
+
String orientationString;
switch (orientation) {
case ORIENTATION_NORMAL:
@@ -277,48 +278,21 @@
}
/**
- * Copies the thumbnail data out of the filename and puts it in the Exif
- * data associated with the file used to create this object. You must call
- * "commitChanges()" at some point to commit the changes.
+ * Returns the latitude and longitude value in a float array. The first element is
+ * the latitude, and the second element is the longitude.
*/
- public boolean appendThumbnail(String thumbnailFileName) {
- if (!mSavedAttributes) {
- throw new RuntimeException("Must call saveAttributes "
- + "before calling appendThumbnail");
- }
- mHasThumbnail = appendThumbnailNative(mFilename, thumbnailFileName);
- return mHasThumbnail;
- }
-
- public boolean hasThumbnail() {
- if (!mSavedAttributes) {
- getAttributes();
- }
- return mHasThumbnail;
- }
-
- public byte[] getThumbnail() {
- return getThumbnailNative(mFilename);
- }
-
- public static float[] getLatLng(HashMap<String, String> exifData) {
- if (exifData == null) {
- return null;
- }
-
- String latValue = exifData.get(ExifInterface.TAG_GPS_LATITUDE);
- String latRef = exifData.get(ExifInterface.TAG_GPS_LATITUDE_REF);
- String lngValue = exifData.get(ExifInterface.TAG_GPS_LONGITUDE);
- String lngRef = exifData.get(ExifInterface.TAG_GPS_LONGITUDE_REF);
+ public float[] getLatLong() {
+ String latValue = mAttributes.get(ExifInterface.TAG_GPS_LATITUDE);
+ String latRef = mAttributes.get(ExifInterface.TAG_GPS_LATITUDE_REF);
+ String lngValue = mAttributes.get(ExifInterface.TAG_GPS_LONGITUDE);
+ String lngRef = mAttributes.get(ExifInterface.TAG_GPS_LONGITUDE_REF);
float[] latlng = null;
if (latValue != null && latRef != null
&& lngValue != null && lngRef != null) {
latlng = new float[2];
- latlng[0] = ExifInterface.convertRationalLatLonToFloat(
- latValue, latRef);
- latlng[1] = ExifInterface.convertRationalLatLonToFloat(
- lngValue, lngRef);
+ latlng[0] = convertRationalLatLonToFloat(latValue, latRef);
+ latlng[1] = convertRationalLatLonToFloat(lngValue, lngRef);
}
return latlng;
@@ -327,14 +301,12 @@
private static SimpleDateFormat sFormatter =
new SimpleDateFormat("yyyy:MM:dd HH:mm:ss");
- // Returns number of milliseconds since Jan. 1, 1970, midnight GMT.
- // Returns -1 if the date time information if not available.
- public static long getDateTime(HashMap<String, String> exifData) {
- if (exifData == null) {
- return -1;
- }
-
- String dateTimeString = exifData.get(ExifInterface.TAG_DATETIME);
+ /**
+ * Returns number of milliseconds since Jan. 1, 1970, midnight GMT.
+ * Returns -1 if the date time information if not available.
+ */
+ public long getDateTime() {
+ String dateTimeString = mAttributes.get(TAG_DATETIME);
if (dateTimeString == null) return -1;
ParsePosition pos = new ParsePosition(0);
@@ -347,7 +319,7 @@
}
}
- public static float convertRationalLatLonToFloat(
+ private static float convertRationalLatLonToFloat(
String rationalString, String ref) {
try {
String [] parts = rationalString.split(",");
@@ -377,42 +349,6 @@
}
}
- public static String convertRationalLatLonToDecimalString(
- String rationalString, String ref, boolean usePositiveNegative) {
- float result = convertRationalLatLonToFloat(rationalString, ref);
-
- String preliminaryResult = String.valueOf(result);
- if (usePositiveNegative) {
- String neg = (ref.equals("S") || ref.equals("E")) ? "-" : "";
- return neg + preliminaryResult;
- } else {
- return preliminaryResult + String.valueOf((char) 186) + " "
- + ref;
- }
- }
-
- public static String makeLatLongString(double d) {
- d = Math.abs(d);
-
- int degrees = (int) d;
-
- double remainder = d - degrees;
- int minutes = (int) (remainder * 60D);
- // really seconds * 1000
- int seconds = (int) (((remainder * 60D) - minutes) * 60D * 1000D);
-
- String retVal = degrees + "/1," + minutes + "/1," + seconds + "/1000";
- return retVal;
- }
-
- public static String makeLatStringRef(double lat) {
- return lat >= 0D ? "N" : "S";
- }
-
- public static String makeLonStringRef(double lon) {
- return lon >= 0D ? "W" : "E";
- }
-
private native boolean appendThumbnailNative(String fileName,
String thumbnailFileName);
diff --git a/media/java/android/media/MediaScanner.java b/media/java/android/media/MediaScanner.java
index f6d30e0..d9127e7 100644
--- a/media/java/android/media/MediaScanner.java
+++ b/media/java/android/media/MediaScanner.java
@@ -719,16 +719,20 @@
values.put(Audio.Media.IS_MUSIC, music);
values.put(Audio.Media.IS_PODCAST, podcasts);
} else if (mFileType == MediaFile.FILE_TYPE_JPEG) {
- HashMap<String, String> exifData =
- ExifInterface.loadExifData(entry.mPath);
- if (exifData != null) {
- float[] latlng = ExifInterface.getLatLng(exifData);
+ ExifInterface exif = null;
+ try {
+ exif = new ExifInterface(entry.mPath);
+ } catch (IOException ex) {
+ // exif is null
+ }
+ if (exif != null) {
+ float[] latlng = exif.getLatLong();
if (latlng != null) {
values.put(Images.Media.LATITUDE, latlng[0]);
values.put(Images.Media.LONGITUDE, latlng[1]);
}
- long time = ExifInterface.getDateTime(exifData);
+ long time = exif.getDateTime();
if (time != -1) {
values.put(Images.Media.DATE_TAKEN, time);
}
