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Commit f34709f3 authored by Aurélien Pomini's avatar Aurélien Pomini
Browse files

Add a recycle check in WallpaperLocalColorExtractor 

Alternative to ag/24403729.

First, this CL makes ImageWallpaper and WallpaperLocalColorExtractor
share the same lock.

Sharing the same lock simplifies the concurrency logic. Since both
ImageWallpaper and WallpaperLocalColorExtractor use the same
single-threaded @LongExecutor for their long operations, their
operations are already atomic but this is rather implicit. We make this
explicit by sharing the same lock.

Second, we add a recycle() check before calling createScaledBitmap in
WallpaperLocalColorExtractor, to avoid a concurrency bug where a new
image is loaded by ImageWallpaper before the color extraction of the
previous image could take place.

By sharing the lock, ImageWallpaper does (recycle(), mBitmap=newBitmap,
startColorExtraction(mBitmap)) atomically with regard to
WallpaperLocalColorExtractor. So when trying to extract colors, we
are guaranteed that either the bitmap is the most recent one, either it
is recycled.

Bug: 292492981
Test: atest ImageWallpaperTest
Test: atest WallpaperLocalColorExtractorTest
Change-Id: Ib5bccaaa7ebb4371feccfc7f5c8407410b8ba59b
parent 53a70ac4

packages/SystemUI/src/com/android/systemui/wallpapers/ImageWallpaper.java

+1 −0
Original line number Diff line number Diff line
@@ -133,6 +133,7 @@ public class ImageWallpaper extends WallpaperService { 
            setShowForAllUsers(true);

            mWallpaperLocalColorExtractor = new WallpaperLocalColorExtractor(

                    mLongExecutor,

                    mLock,

                    new WallpaperLocalColorExtractor.WallpaperLocalColorExtractorCallback() {

                        @Override

                        public void onColorsProcessed(List<RectF> regions,

packages/SystemUI/src/com/android/systemui/wallpapers/WallpaperLocalColorExtractor.java

+10 −1
Original line number Diff line number Diff line
@@ -61,7 +61,7 @@ public class WallpaperLocalColorExtractor { 
    private int mBitmapWidth = -1;

    private int mBitmapHeight = -1;



    private final Object mLock = new Object();

    private final Object mLock;



    private final List<RectF> mPendingRegions = new ArrayList<>();

    private final Set<RectF> mProcessedRegions = new ArraySet<>();
@@ -102,12 +102,15 @@ public class WallpaperLocalColorExtractor { 
    /**

     * Creates a new color extractor.

     * @param longExecutor the executor on which the color extraction will be performed

     * @param lock the lock object to use for computing colors or processing the bitmap

     * @param wallpaperLocalColorExtractorCallback an interface to handle the callbacks from

     *                                        the color extractor.

     */

    public WallpaperLocalColorExtractor(@LongRunning Executor longExecutor,

            Object lock,

            WallpaperLocalColorExtractorCallback wallpaperLocalColorExtractorCallback) {

        mLongExecutor = longExecutor;

        mLock = lock;

        mWallpaperLocalColorExtractorCallback = wallpaperLocalColorExtractorCallback;

    }
@@ -149,6 +152,12 @@ public class WallpaperLocalColorExtractor { 


    private void onBitmapChangedSynchronized(@NonNull Bitmap bitmap) {

        synchronized (mLock) {

            if (bitmap.isRecycled()) {

                // ImageWallpaper loaded a new bitmap before the extraction of the previous one

                // In that case, ImageWallpaper also scheduled the extraction of the next bitmap

                Log.i(TAG, "Wallpaper has changed; deferring color extraction");

                return;

            }

            if (bitmap.getWidth() <= 0 || bitmap.getHeight() <= 0) {

                Log.e(TAG, "Attempt to extract colors from an invalid bitmap");

                return;

packages/SystemUI/tests/src/com/android/systemui/wallpapers/WallpaperLocalColorExtractorTest.java

+1 −0
Original line number Diff line number Diff line
@@ -109,6 +109,7 @@ public class WallpaperLocalColorExtractorTest extends SysuiTestCase { 


        WallpaperLocalColorExtractor colorExtractor = new WallpaperLocalColorExtractor(

                mBackgroundExecutor,

                new Object(),

                new WallpaperLocalColorExtractor.WallpaperLocalColorExtractorCallback() {

                    @Override

                    public void onColorsProcessed(List<RectF> regions,