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Commit 6398343e authored by Jeff Sharkey's avatar Jeff Sharkey
Browse files

Return EXIF thumbnails when available. 

Adds new ExifInterface method to extract the thumbnail range from
a larger image file, and use that to return an AssetFileDescriptor.

When decoding an AssetFileDescriptor thumbnail with offsets, read out
the raw data entirely, since Skia uses lseek() aggressively.

Bug: 10412208
Change-Id: I7906cdf82c0c3794cec7043c801a86f66efeb143
parent bd3b9025

core/java/android/provider/DocumentsContract.java

+45 −11
Original line number Diff line number Diff line
@@ -16,6 +16,9 @@ 


package android.provider;



import static android.net.TrafficStats.KB_IN_BYTES;

import static libcore.io.OsConstants.SEEK_SET;



import android.content.ContentProvider;

import android.content.ContentResolver;

import android.content.ContentValues;
@@ -36,7 +39,10 @@ import android.util.Log; 


import com.google.android.collect.Lists;



import libcore.io.ErrnoException;

import libcore.io.IoBridge;

import libcore.io.IoUtils;

import libcore.io.Libcore;



import java.io.FileDescriptor;

import java.io.IOException;
@@ -527,25 +533,53 @@ public final class DocumentsContract { 
     * @return decoded thumbnail, or {@code null} if problem was encountered.

     */

    public static Bitmap getThumbnail(ContentResolver resolver, Uri documentUri, Point size) {

        final Bundle opts = new Bundle();

        opts.putParcelable(EXTRA_THUMBNAIL_SIZE, size);

        final Bundle openOpts = new Bundle();

        openOpts.putParcelable(DocumentsContract.EXTRA_THUMBNAIL_SIZE, size);



        AssetFileDescriptor afd = null;

        try {

            afd = resolver.openTypedAssetFileDescriptor(documentUri, "image/*", opts);

            afd = resolver.openTypedAssetFileDescriptor(documentUri, "image/*", openOpts);



            final FileDescriptor fd = afd.getFileDescriptor();

            final BitmapFactory.Options bitmapOpts = new BitmapFactory.Options();



            bitmapOpts.inJustDecodeBounds = true;

            BitmapFactory.decodeFileDescriptor(fd, null, bitmapOpts);



            final int widthSample = bitmapOpts.outWidth / size.x;

            final int heightSample = bitmapOpts.outHeight / size.y;



            bitmapOpts.inJustDecodeBounds = false;

            bitmapOpts.inSampleSize = Math.min(widthSample, heightSample);

            return BitmapFactory.decodeFileDescriptor(fd, null, bitmapOpts);

            final long offset = afd.getStartOffset();

            final long length = afd.getDeclaredLength();



            // Some thumbnails might be a region inside a larger file, such as

            // an EXIF thumbnail. Since BitmapFactory aggressively seeks around

            // the entire file, we read the region manually.

            byte[] region = null;

            if (offset > 0 && length <= 64 * KB_IN_BYTES) {

                region = new byte[(int) length];

                Libcore.os.lseek(fd, offset, SEEK_SET);

                if (IoBridge.read(fd, region, 0, region.length) != region.length) {

                    region = null;

                }

            }



            // We requested a rough thumbnail size, but the remote size may have

            // returned something giant, so defensively scale down as needed.

            final BitmapFactory.Options opts = new BitmapFactory.Options();

            opts.inJustDecodeBounds = true;

            if (region != null) {

                BitmapFactory.decodeByteArray(region, 0, region.length, opts);

            } else {

                BitmapFactory.decodeFileDescriptor(fd, null, opts);

            }



            final int widthSample = opts.outWidth / size.x;

            final int heightSample = opts.outHeight / size.y;



            opts.inJustDecodeBounds = false;

            opts.inSampleSize = Math.min(widthSample, heightSample);

            Log.d(TAG, "Decoding with sample size " + opts.inSampleSize);

            if (region != null) {

                return BitmapFactory.decodeByteArray(region, 0, region.length, opts);

            } else {

                return BitmapFactory.decodeFileDescriptor(fd, null, opts);

            }

        } catch (ErrnoException e) {

            Log.w(TAG, "Failed to load thumbnail for " + documentUri + ": " + e);

            return null;

        } catch (IOException e) {

            Log.w(TAG, "Failed to load thumbnail for " + documentUri + ": " + e);

            return null;

media/java/android/media/ExifInterface.java

+16 −0
Original line number Diff line number Diff line
@@ -290,6 +290,20 @@ public class ExifInterface { 
        }

    }



    /**

     * Returns the offset and length of thumbnail inside the JPEG file, or

     * {@code null} if there is no thumbnail.

     *

     * @return two-element array, the offset in the first value, and length in

     *         the second, or {@code null} if no thumbnail was found.

     * @hide

     */

    public long[] getThumbnailRange() {

        synchronized (sLock) {

            return getThumbnailRangeNative(mFilename);

        }

    }



    /**

     * Stores the latitude and longitude value in a float array. The first element is

     * the latitude, and the second element is the longitude. Returns false if the
@@ -416,4 +430,6 @@ public class ExifInterface { 
    private native void commitChangesNative(String fileName);



    private native byte[] getThumbnailNative(String fileName);



    private native long[] getThumbnailRangeNative(String fileName);

}

packages/ExternalStorageProvider/src/com/android/externalstorage/ExternalStorageProvider.java

+36 −1
Original line number Diff line number Diff line
@@ -20,10 +20,13 @@ import android.content.ContentProvider; 
import android.content.ContentResolver;

import android.content.ContentValues;

import android.content.UriMatcher;

import android.content.res.AssetFileDescriptor;

import android.database.Cursor;

import android.database.MatrixCursor;

import android.database.MatrixCursor.RowBuilder;

import android.media.ExifInterface;

import android.net.Uri;

import android.os.Bundle;

import android.os.Environment;

import android.os.ParcelFileDescriptor;

import android.provider.DocumentsContract;
@@ -296,7 +299,6 @@ public class ExternalStorageProvider extends ContentProvider { 
                final Root root = mRoots.get(DocumentsContract.getRootId(uri));

                final String docId = DocumentsContract.getDocId(uri);



                // TODO: offer as thumbnail

                final File file = docIdToFile(root, docId);

                return ParcelFileDescriptor.open(file, ContentResolver.modeToMode(uri, mode));

            }
@@ -306,6 +308,39 @@ public class ExternalStorageProvider extends ContentProvider { 
        }

    }



    @Override

    public AssetFileDescriptor openTypedAssetFile(Uri uri, String mimeTypeFilter, Bundle opts)

            throws FileNotFoundException {

        if (opts == null || !opts.containsKey(DocumentsContract.EXTRA_THUMBNAIL_SIZE)) {

            return super.openTypedAssetFile(uri, mimeTypeFilter, opts);

        }



        switch (sMatcher.match(uri)) {

            case URI_DOCS_ID: {

                final Root root = mRoots.get(DocumentsContract.getRootId(uri));

                final String docId = DocumentsContract.getDocId(uri);



                final File file = docIdToFile(root, docId);

                final ParcelFileDescriptor pfd = ParcelFileDescriptor.open(

                        file, ParcelFileDescriptor.MODE_READ_ONLY);



                try {

                    final ExifInterface exif = new ExifInterface(file.getAbsolutePath());

                    final long[] thumb = exif.getThumbnailRange();

                    if (thumb != null) {

                        return new AssetFileDescriptor(pfd, thumb[0], thumb[1]);

                    }

                } catch (IOException e) {

                }



                return new AssetFileDescriptor(pfd, 0, AssetFileDescriptor.UNKNOWN_LENGTH);

            }

            default: {

                throw new UnsupportedOperationException("Unsupported Uri " + uri);

            }

        }

    }



    @Override

    public Uri insert(Uri uri, ContentValues values) {

        switch (sMatcher.match(uri)) {