From 52d63e7e4c3e0db42f72f8f55453a47d62b8aa22 Mon Sep 17 00:00:00 2001
From: Ahan Wu <ahanwu@google.com>
Date: Tue, 12 Apr 2022 10:19:52 +0000
Subject: [PATCH] DO NOT MERGE: Don't do heavy operation while in the
 synchronized block

We read the wallpaper within the synchronized block, this is a long time
operation, might block the other thread who is going to obtain the lock.
So we have to move the operation beyond the synchronized block.

Bug: 228435216
Test: atest WallpaperManagerTest#testPeekWallpaperNotBlockingOtherThread
Change-Id: Ic2a947b473710ffe68db436586769858950588a4
---
 core/java/android/app/WallpaperManager.java | 38 +++++++++++----------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/core/java/android/app/WallpaperManager.java b/core/java/android/app/WallpaperManager.java
index 0a18588e0131d..e022ca3066744 100644
--- a/core/java/android/app/WallpaperManager.java
+++ b/core/java/android/app/WallpaperManager.java
@@ -67,7 +67,6 @@ import android.os.ParcelFileDescriptor;
 import android.os.RemoteException;
 import android.os.StrictMode;
 import android.os.SystemProperties;
-import android.service.wallpaper.WallpaperService;
 import android.text.TextUtils;
 import android.util.ArrayMap;
 import android.util.ArraySet;
@@ -559,23 +558,26 @@ public class WallpaperManager {
                 }
                 mCachedWallpaper = null;
                 mCachedWallpaperUserId = 0;
-                try {
-                    mCachedWallpaper = getCurrentWallpaperLocked(
-                            context, userId, hardware, cmProxy);
-                    mCachedWallpaperUserId = userId;
-                } catch (OutOfMemoryError e) {
-                    Log.w(TAG, "Out of memory loading the current wallpaper: " + e);
-                } catch (SecurityException e) {
-                    if (context.getApplicationInfo().targetSdkVersion < Build.VERSION_CODES.O_MR1) {
-                        Log.w(TAG, "No permission to access wallpaper, suppressing"
-                                + " exception to avoid crashing legacy app.");
-                    } else {
-                        // Post-O apps really most sincerely need the permission.
-                        throw e;
+            }
+            try {
+                Bitmap currentWallpaper = getCurrentWallpaperLocked(
+                        context, userId, hardware, cmProxy);
+                if (currentWallpaper != null) {
+                    synchronized (this) {
+                        mCachedWallpaper = currentWallpaper;
+                        mCachedWallpaperUserId = userId;
+                        return mCachedWallpaper;
                     }
                 }
-                if (mCachedWallpaper != null) {
-                    return mCachedWallpaper;
+            } catch (OutOfMemoryError e) {
+                Log.w(TAG, "Out of memory loading the current wallpaper: " + e);
+            } catch (SecurityException e) {
+                if (context.getApplicationInfo().targetSdkVersion < Build.VERSION_CODES.O_MR1) {
+                    Log.w(TAG, "No permission to access wallpaper, suppressing"
+                            + " exception to avoid crashing legacy app.");
+                } else {
+                    // Post-O apps really most sincerely need the permission.
+                    throw e;
                 }
             }
             if (returnDefault) {
@@ -2472,7 +2474,7 @@ public class WallpaperManager {
          *
          * @param colors Wallpaper color info, {@code null} when not available.
          * @param which A combination of {@link #FLAG_LOCK} and {@link #FLAG_SYSTEM}
-         * @see WallpaperService.Engine#onComputeColors()
+         * @see android.service.wallpaper.WallpaperService.Engine#onComputeColors()
          */
         void onColorsChanged(@Nullable WallpaperColors colors, int which);
 
@@ -2484,7 +2486,7 @@ public class WallpaperManager {
          * @param colors Wallpaper color info, {@code null} when not available.
          * @param which A combination of {@link #FLAG_LOCK} and {@link #FLAG_SYSTEM}
          * @param userId Owner of the wallpaper
-         * @see WallpaperService.Engine#onComputeColors()
+         * @see android.service.wallpaper.WallpaperService.Engine#onComputeColors()
          * @hide
          */
         default void onColorsChanged(@Nullable WallpaperColors colors, int which, int userId) {