Support wallpaper on secondary displays.(5/N)

1. Pull DisplayData from WallpaperData, so the rendering size will only
related to the display.
2. In the previous CL, we provided a new property "supportsMultipleDisplays"
that lets the WallpaperManagerService or wallpaper selector know that the
component can be rendered on each display at the same time. In this CL we
provide a fallback mechanism. If the selected wallpaper service does not
support multiple displays, we will display the default image wallpaper on
the secondary display.
3. Add private access for some fields and methods.(by IDE reminder)

Bug: 115486823
Test: atest WallpaperManagerTest
Test: atest WmTests
Test: atest ActivityManagerMultiDisplayTests
Change-Id: I2fa6ad5dc39a84e317680399e70178ca258a22ae

1 files changed, 214 insertions, 112 deletions

diff --git a/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java b/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
index 64ff9cf21ba0..2157c9950457 100644
--- a/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
+++ b/services/core/java/com/android/server/wallpaper/WallpaperManagerService.java
@@ -60,6 +60,7 @@ import android.graphics.Rect;
 import android.hardware.display.DisplayManager;
 import android.os.Binder;
 import android.os.Bundle;
+import android.os.Debug;
 import android.os.Environment;
 import android.os.FileObserver;
 import android.os.FileUtils;
@@ -85,6 +86,7 @@ import android.system.Os;
 import android.util.EventLog;
 import android.util.Slog;
 import android.util.SparseArray;
+import android.util.SparseBooleanArray;
 import android.util.Xml;
 import android.view.Display;
 import android.view.IWindowManager;
@@ -120,12 +122,13 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
 import java.util.function.Consumer;
+import java.util.function.Predicate;
 
 public class WallpaperManagerService extends IWallpaperManager.Stub
         implements IWallpaperManagerService {
-    static final String TAG = "WallpaperManagerService";
-    static final boolean DEBUG = false;
-    static final boolean DEBUG_LIVE = DEBUG || true;
+    private static final String TAG = "WallpaperManagerService";
+    private static final boolean DEBUG = false;
+    private static final boolean DEBUG_LIVE = true;
 
     public static class Lifecycle extends SystemService {
         private IWallpaperManagerService mService;
@@ -163,14 +166,14 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         }
     }
 
-    final Object mLock = new Object();
+    private final Object mLock = new Object();
 
     /**
      * Minimum time between crashes of a wallpaper service for us to consider
      * restarting it vs. just reverting to the static wallpaper.
      */
-    static final long MIN_WALLPAPER_CRASH_TIME = 10000;
-    static final int MAX_WALLPAPER_COMPONENT_LOG_LENGTH = 128;
+    private static final long MIN_WALLPAPER_CRASH_TIME = 10000;
+    private static final int MAX_WALLPAPER_COMPONENT_LOG_LENGTH = 128;
     static final String WALLPAPER = "wallpaper_orig";
     static final String WALLPAPER_CROP = "wallpaper";
     static final String WALLPAPER_LOCK_ORIG = "wallpaper_lock_orig";
@@ -178,7 +181,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
     static final String WALLPAPER_INFO = "wallpaper_info.xml";
 
     // All the various per-user state files we need to be aware of
-    static final String[] sPerUserFiles = new String[] {
+    private static final String[] sPerUserFiles = new String[] {
         WALLPAPER, WALLPAPER_CROP,
         WALLPAPER_LOCK_ORIG, WALLPAPER_LOCK_CROP,
         WALLPAPER_INFO
@@ -335,7 +338,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         }
     }
 
-    void notifyLockWallpaperChanged() {
+    private void notifyLockWallpaperChanged() {
         final IWallpaperManagerCallback cb = mKeyguardListener;
         if (cb != null) {
             try {
@@ -487,7 +490,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         boolean success = false;
 
         // Only generate crop for default display.
-        final WallpaperData.DisplayData wpData = getDisplayDataOrCreate(wallpaper, DEFAULT_DISPLAY);
+        final DisplayData wpData = getDisplayDataOrCreate(DEFAULT_DISPLAY);
         Rect cropHint = new Rect(wallpaper.cropHint);
 
         if (DEBUG) {
@@ -640,11 +643,11 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         }
     }
 
-    final Context mContext;
-    final IWindowManager mIWindowManager;
-    final IPackageManager mIPackageManager;
-    final MyPackageMonitor mMonitor;
-    final AppOpsManager mAppOpsManager;
+    private final Context mContext;
+    private final IWindowManager mIWindowManager;
+    private final IPackageManager mIPackageManager;
+    private final MyPackageMonitor mMonitor;
+    private final AppOpsManager mAppOpsManager;
 
     private final DisplayManager mDisplayManager;
     private final DisplayManager.DisplayListener mDisplayListener =
@@ -654,11 +657,23 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         public void onDisplayAdded(int displayId) {
             synchronized (mLock) {
                 if (mLastWallpaper != null) {
-                    final WallpaperConnection.DisplayConnector connector =
-                            mLastWallpaper.connection.getDisplayConnectorOrCreate(displayId);
-                    if (connector == null) return;
-
-                    connector.connectLocked(mLastWallpaper.connection, mLastWallpaper);
+                    if (supportsMultiDisplay(mLastWallpaper.connection)) {
+                        final WallpaperConnection.DisplayConnector connector =
+                                mLastWallpaper.connection.getDisplayConnectorOrCreate(displayId);
+                        if (connector == null) return;
+                        connector.connectLocked(mLastWallpaper.connection, mLastWallpaper);
+                        return;
+                    }
+                    // System wallpaper does not support multiple displays, attach this display to
+                    // the fallback wallpaper.
+                    if (mFallbackWallpaper != null) {
+                        final WallpaperConnection.DisplayConnector connector = mFallbackWallpaper
+                                .connection.getDisplayConnectorOrCreate(displayId);
+                        if (connector == null) return;
+                        connector.connectLocked(mFallbackWallpaper.connection, mFallbackWallpaper);
+                    } else {
+                        Slog.w(TAG, "No wallpaper can be added to the new display");
+                    }
                 }
             }
         }
@@ -667,12 +682,19 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         public void onDisplayRemoved(int displayId) {
             synchronized (mLock) {
                 if (mLastWallpaper != null) {
-                    final WallpaperConnection.DisplayConnector connector =
-                            mLastWallpaper.connection.getDisplayConnectorOrCreate(displayId);
+                    WallpaperData targetWallpaper = null;
+                    if (mLastWallpaper.connection.containsDisplay(displayId)) {
+                        targetWallpaper = mLastWallpaper;
+                    } else if (mFallbackWallpaper.connection.containsDisplay(displayId)) {
+                        targetWallpaper = mFallbackWallpaper;
+                    }
+                    if (targetWallpaper == null) return;
+                    WallpaperConnection.DisplayConnector connector =
+                            targetWallpaper.connection.getDisplayConnectorOrCreate(displayId);
                     if (connector == null) return;
                     connector.disconnectLocked();
-                    mLastWallpaper.connection.removeDisplayConnector(displayId);
-                    mLastWallpaper.removeDisplayData(displayId);
+                    targetWallpaper.connection.removeDisplayConnector(displayId);
+                    removeDisplayData(displayId);
                 }
             }
         }
@@ -686,35 +708,40 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
      * Map of color listeners per user id.
      * The key will be the id of a user or UserHandle.USER_ALL - for wildcard listeners.
      */
-    final SparseArray<RemoteCallbackList<IWallpaperManagerCallback>> mColorsChangedListeners;
-    WallpaperData mLastWallpaper;
-    IWallpaperManagerCallback mKeyguardListener;
-    boolean mWaitingForUnlock;
-    boolean mShuttingDown;
+    private final SparseArray<RemoteCallbackList<IWallpaperManagerCallback>>
+            mColorsChangedListeners;
+    private WallpaperData mLastWallpaper;
+    private IWallpaperManagerCallback mKeyguardListener;
+    private boolean mWaitingForUnlock;
+    private boolean mShuttingDown;
 
     /**
      * ID of the current wallpaper, changed every time anything sets a wallpaper.
      * This is used for external detection of wallpaper update activity.
      */
-    int mWallpaperId;
+    private int mWallpaperId;
 
     /**
      * Name of the component used to display bitmap wallpapers from either the gallery or
      * built-in wallpapers.
      */
-    final ComponentName mImageWallpaper;
+    private final ComponentName mImageWallpaper;
 
     /**
      * Name of the default wallpaper component; might be different from mImageWallpaper
      */
-    final ComponentName mDefaultWallpaperComponent;
+    private final ComponentName mDefaultWallpaperComponent;
 
-    final SparseArray<WallpaperData> mWallpaperMap = new SparseArray<WallpaperData>();
-    final SparseArray<WallpaperData> mLockWallpaperMap = new SparseArray<WallpaperData>();
+    private final SparseArray<WallpaperData> mWallpaperMap = new SparseArray<WallpaperData>();
+    private final SparseArray<WallpaperData> mLockWallpaperMap = new SparseArray<WallpaperData>();
 
-    final SparseArray<Boolean> mUserRestorecon = new SparseArray<Boolean>();
-    int mCurrentUserId = UserHandle.USER_NULL;
-    boolean mInAmbientMode;
+    private SparseArray<DisplayData> mDisplayDatas = new SparseArray<>();
+
+    private WallpaperData mFallbackWallpaper;
+
+    private final SparseBooleanArray mUserRestorecon = new SparseBooleanArray();
+    private int mCurrentUserId = UserHandle.USER_NULL;
+    private boolean mInAmbientMode;
 
     static class WallpaperData {
 
@@ -780,18 +807,6 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         private RemoteCallbackList<IWallpaperManagerCallback> callbacks
                 = new RemoteCallbackList<IWallpaperManagerCallback>();
 
-        private static final class DisplayData {
-            int mWidth = -1;
-            int mHeight = -1;
-            final Rect mPadding = new Rect(0, 0, 0, 0);
-            final int mDisplayId;
-
-            DisplayData(int displayId) {
-                mDisplayId = displayId;
-            }
-        }
-        private SparseArray<DisplayData> mDisplayDatas = new SparseArray<>();
-
         /**
          * The crop hint supplied for displaying a subset of the source image
          */
@@ -812,24 +827,34 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         boolean sourceExists() {
             return wallpaperFile.exists();
         }
+    }
 
-        void removeDisplayData(int displayId) {
-            mDisplayDatas.remove(displayId);
+    private static final class DisplayData {
+        int mWidth = -1;
+        int mHeight = -1;
+        final Rect mPadding = new Rect(0, 0, 0, 0);
+        final int mDisplayId;
+
+        DisplayData(int displayId) {
+            mDisplayId = displayId;
         }
     }
 
-    private WallpaperData.DisplayData getDisplayDataOrCreate(WallpaperData data, int displayId) {
-        WallpaperData.DisplayData wpdData = data.mDisplayDatas.get(displayId);
+    private void removeDisplayData(int displayId) {
+        mDisplayDatas.remove(displayId);
+    }
+
+    private DisplayData getDisplayDataOrCreate(int displayId) {
+        DisplayData wpdData = mDisplayDatas.get(displayId);
         if (wpdData == null) {
-            wpdData = new WallpaperData.DisplayData(displayId);
+            wpdData = new DisplayData(displayId);
             ensureSaneWallpaperDisplaySize(wpdData, displayId);
-            data.mDisplayDatas.append(displayId, wpdData);
+            mDisplayDatas.append(displayId, wpdData);
         }
         return wpdData;
     }
 
-    private void ensureSaneWallpaperDisplaySize(WallpaperData.DisplayData wpdData,
-            int displayId) {
+    private void ensureSaneWallpaperDisplaySize(DisplayData wpdData, int displayId) {
         // We always want to have some reasonable width hint.
         final int baseSize = getMaximumSizeDimension(displayId);
         if (wpdData.mWidth < baseSize) {
@@ -842,12 +867,16 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
 
     private int getMaximumSizeDimension(int displayId) {
         Display display = mDisplayManager.getDisplay(displayId);
+        if (display == null) {
+            Slog.w(TAG, "Invalid displayId=" + displayId + " " + Debug.getCallers(4));
+            display = mDisplayManager.getDisplay(DEFAULT_DISPLAY);
+        }
         return display.getMaximumSizeDimension();
     }
 
-    void forEachDisplayData(WallpaperData data, Consumer<WallpaperData.DisplayData> action) {
-        for (int i = data.mDisplayDatas.size() - 1; i >= 0; i--) {
-            final WallpaperData.DisplayData wpdData = data.mDisplayDatas.valueAt(i);
+    void forEachDisplayData(Consumer<DisplayData> action) {
+        for (int i = mDisplayDatas.size() - 1; i >= 0; i--) {
+            final DisplayData wpdData = mDisplayDatas.valueAt(i);
             action.accept(wpdData);
         }
     }
@@ -859,6 +888,36 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         return mWallpaperId;
     }
 
+    private boolean supportsMultiDisplay(WallpaperConnection connection) {
+        if (connection != null) {
+            return connection.mInfo == null // This is image wallpaper
+                    || connection.mInfo.supportsMultipleDisplays();
+        }
+        return false;
+    }
+
+    private void updateFallbackConnection() {
+        if (mLastWallpaper == null || mFallbackWallpaper == null) return;
+        final WallpaperConnection systemConnection = mLastWallpaper.connection;
+        final WallpaperConnection fallbackConnection = mFallbackWallpaper.connection;
+        if (supportsMultiDisplay(systemConnection)
+                && fallbackConnection.getConnectedEngineSize() != 0) {
+            fallbackConnection.forEachDisplayConnector(
+                    WallpaperConnection.DisplayConnector::disconnectLocked);
+            fallbackConnection.mDisplayConnector.clear();
+        } else {
+            fallbackConnection.appendConnectorWithCondition(display ->
+                    fallbackConnection.isUsableDisplay(display)
+                            && display.getDisplayId() != DEFAULT_DISPLAY
+                            && !fallbackConnection.containsDisplay(display.getDisplayId()));
+            fallbackConnection.forEachDisplayConnector(connector -> {
+                if (connector.mEngine == null) {
+                    connector.connectLocked(fallbackConnection, mFallbackWallpaper);
+                }
+            });
+        }
+    }
+
     class WallpaperConnection extends IWallpaperConnection.Stub
             implements ServiceConnection {
 
@@ -877,8 +936,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
             }
 
             void ensureStatusHandled() {
-                final WallpaperData.DisplayData wpdData = getDisplayDataOrCreate(mWallpaper,
-                        mDisplayId);
+                final DisplayData wpdData = getDisplayDataOrCreate(mDisplayId);
                 if (mDimensionsChanged) {
                     try {
                         mEngine.setDesiredSize(wpdData.mWidth, wpdData.mHeight);
@@ -906,8 +964,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                     return;
                 }
 
-                final WallpaperData.DisplayData wpdData = getDisplayDataOrCreate(wallpaper,
-                        mDisplayId);
+                final DisplayData wpdData = getDisplayDataOrCreate(mDisplayId);
                 try {
                     connection.mService.attach(connection, mToken, TYPE_WALLPAPER, false,
                             wpdData.mWidth, wpdData.mHeight,
@@ -982,19 +1039,33 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         }
 
         private void initDisplayState() {
+            // Do not initialize fallback wallpaper
+            if (!mWallpaper.equals(mFallbackWallpaper)) {
+                if (supportsMultiDisplay(this)) {
+                    // The system wallpaper is image wallpaper or it can supports multiple displays.
+                    appendConnectorWithCondition(this::isUsableDisplay);
+                } else {
+                    // The system wallpaper does not support multiple displays, so just attach it on
+                    // default display.
+                    mDisplayConnector.append(DEFAULT_DISPLAY,
+                            new DisplayConnector(DEFAULT_DISPLAY));
+                }
+            }
+        }
+
+        private void appendConnectorWithCondition(Predicate<Display> tester) {
             final Display[] displays = mDisplayManager.getDisplays();
             for (Display display : displays) {
-                if (isUsableDisplay(display)) {
+                if (tester.test(display)) {
                     final int displayId = display.getDisplayId();
-                    mDisplayConnector.append(displayId, new DisplayConnector(displayId));
+                    mDisplayConnector.append(displayId,
+                            new DisplayConnector(displayId));
                 }
             }
         }
 
-        // TODO(b/115486823) Support the system decorations change at runtime.
         private boolean isUsableDisplay(Display display) {
             return display != null &&  display.hasAccess(mClientUid)
-                    // TODO(b/114338689) Use WindowManager.supportsSystemDecorations when ready
                     && (display.supportsSystemDecorations()
                             || display.getDisplayId() == DEFAULT_DISPLAY);
         }
@@ -1027,6 +1098,10 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
             return connector;
         }
 
+        boolean containsDisplay(int displayId) {
+            return mDisplayConnector.get(displayId) != null;
+        }
+
         void removeDisplayConnector(int displayId) {
             final DisplayConnector connector = mDisplayConnector.get(displayId);
             if (connector != null) {
@@ -1044,7 +1119,9 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                     // when we have an engine, but I'm not sure about
                     // locking there and anyway we always need to be able to
                     // recover if there is something wrong.
-                    saveSettingsLocked(mWallpaper.userId);
+                    if (!mWallpaper.equals(mFallbackWallpaper)) {
+                        saveSettingsLocked(mWallpaper.userId);
+                    }
                     FgThread.getHandler().removeCallbacks(mResetRunnable);
                 }
             }
@@ -1533,8 +1610,8 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                 // This corrects for mislabeling bugs that might have arisen from move-to
                 // operations involving the wallpaper files.  This isn't timing-critical,
                 // so we do it in the background to avoid holding up the user unlock operation.
-                if (mUserRestorecon.get(userId) != Boolean.TRUE) {
-                    mUserRestorecon.put(userId, Boolean.TRUE);
+                if (!mUserRestorecon.get(userId)) {
+                    mUserRestorecon.put(userId, true);
                     Runnable relabeler = new Runnable() {
                         @Override
                         public void run() {
@@ -1562,7 +1639,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
             for (String filename : sPerUserFiles) {
                 new File(wallpaperDir, filename).delete();
             }
-            mUserRestorecon.remove(userId);
+            mUserRestorecon.delete(userId);
         }
     }
 
@@ -1789,7 +1866,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                 throw new IllegalArgumentException("Cannot find display with id=" + displayId);
             }
 
-            final WallpaperData.DisplayData wpdData = getDisplayDataOrCreate(wallpaper, displayId);
+            final DisplayData wpdData = getDisplayDataOrCreate(displayId);
             if (width != wpdData.mWidth || height != wpdData.mHeight) {
                 wpdData.mWidth = width;
                 wpdData.mHeight = height;
@@ -1826,8 +1903,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
             }
             WallpaperData wallpaper = mWallpaperMap.get(UserHandle.getCallingUserId());
             if (wallpaper != null) {
-                final WallpaperData.DisplayData wpdData = getDisplayDataOrCreate(wallpaper,
-                        displayId);
+                final DisplayData wpdData = getDisplayDataOrCreate(displayId);
                 return wpdData.mWidth;
             } else {
                 return 0;
@@ -1845,8 +1921,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
             }
             WallpaperData wallpaper = mWallpaperMap.get(UserHandle.getCallingUserId());
             if (wallpaper != null) {
-                final WallpaperData.DisplayData wpdData = getDisplayDataOrCreate(wallpaper,
-                        displayId);
+                final DisplayData wpdData = getDisplayDataOrCreate(displayId);
                 return wpdData.mHeight;
             } else {
                 return 0;
@@ -1872,7 +1947,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                 throw new IllegalArgumentException("padding must be positive: " + padding);
             }
 
-            final WallpaperData.DisplayData wpdData = getDisplayDataOrCreate(wallpaper, displayId);
+            final DisplayData wpdData = getDisplayDataOrCreate(displayId);
             if (!padding.equals(wpdData.mPadding)) {
                 wpdData.mPadding.set(padding);
                 if (displayId == DEFAULT_DISPLAY) saveSettingsLocked(userId);
@@ -1940,8 +2015,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                 return null;
             }
             // Only for default display.
-            final WallpaperData.DisplayData wpdData = getDisplayDataOrCreate(wallpaper,
-                    DEFAULT_DISPLAY);
+            final DisplayData wpdData = getDisplayDataOrCreate(DEFAULT_DISPLAY);
             try {
                 if (outParams != null) {
                     outParams.putInt("width", wpdData.mWidth);
@@ -2173,14 +2247,8 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         // We know a-priori that there is no lock-only wallpaper currently
         WallpaperData lockWP = new WallpaperData(userId,
                 WALLPAPER_LOCK_ORIG, WALLPAPER_LOCK_CROP);
-        final WallpaperData.DisplayData lockWPDData = getDisplayDataOrCreate(lockWP,
-                DEFAULT_DISPLAY);
-        final WallpaperData.DisplayData sysWPDData = getDisplayDataOrCreate(sysWP,
-                DEFAULT_DISPLAY);
         lockWP.wallpaperId = sysWP.wallpaperId;
         lockWP.cropHint.set(sysWP.cropHint);
-        lockWPDData.mWidth = sysWPDData.mWidth;
-        lockWPDData.mHeight = sysWPDData.mHeight;
         lockWP.allowBackup = sysWP.allowBackup;
         lockWP.primaryColors = sysWP.primaryColors;
 
@@ -2320,7 +2388,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         return false;
     }
 
-    boolean bindWallpaperComponentLocked(ComponentName componentName, boolean force,
+    private boolean bindWallpaperComponentLocked(ComponentName componentName, boolean force,
             boolean fromUser, WallpaperData wallpaper, IRemoteCallback reply) {
         if (DEBUG_LIVE) {
             Slog.v(TAG, "bindWallpaperComponentLocked: componentName=" + componentName);
@@ -2443,15 +2511,17 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                 Slog.w(TAG, msg);
                 return false;
             }
-            if (wallpaper.userId == mCurrentUserId && mLastWallpaper != null) {
+            if (wallpaper.userId == mCurrentUserId && mLastWallpaper != null
+                    && !wallpaper.equals(mFallbackWallpaper)) {
                 detachWallpaperLocked(mLastWallpaper);
             }
             wallpaper.wallpaperComponent = componentName;
             wallpaper.connection = newConn;
             newConn.mReply = reply;
-            if (wallpaper.userId == mCurrentUserId) {
+            if (wallpaper.userId == mCurrentUserId && !wallpaper.equals(mFallbackWallpaper)) {
                 mLastWallpaper = wallpaper;
             }
+            updateFallbackConnection();
         } catch (RemoteException e) {
             String msg = "Remote exception for " + componentName + "\n" + e;
             if (fromUser) {
@@ -2463,7 +2533,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         return true;
     }
 
-    void detachWallpaperLocked(WallpaperData wallpaper) {
+    private void detachWallpaperLocked(WallpaperData wallpaper) {
         if (wallpaper.connection != null) {
             if (wallpaper.connection.mReply != null) {
                 try {
@@ -2473,7 +2543,8 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                 wallpaper.connection.mReply = null;
             }
             mContext.unbindService(wallpaper.connection);
-            wallpaper.connection.forEachDisplayConnector(connector -> connector.disconnectLocked());
+            wallpaper.connection.forEachDisplayConnector(
+                    WallpaperConnection.DisplayConnector::disconnectLocked);
             wallpaper.connection.mService = null;
             wallpaper.connection.mDisplayConnector.clear();
             wallpaper.connection = null;
@@ -2481,12 +2552,12 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         }
     }
 
-    void clearWallpaperComponentLocked(WallpaperData wallpaper) {
+    private void clearWallpaperComponentLocked(WallpaperData wallpaper) {
         wallpaper.wallpaperComponent = null;
         detachWallpaperLocked(wallpaper);
     }
 
-    void attachServiceLocked(WallpaperConnection conn, WallpaperData wallpaper) {
+    private void attachServiceLocked(WallpaperConnection conn, WallpaperData wallpaper) {
         conn.forEachDisplayConnector(connector-> connector.connectLocked(conn, wallpaper));
     }
 
@@ -2596,8 +2667,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         if (DEBUG) {
             Slog.v(TAG, "writeWallpaperAttributes id=" + wallpaper.wallpaperId);
         }
-        final WallpaperData.DisplayData wpdData = getDisplayDataOrCreate(wallpaper,
-                DEFAULT_DISPLAY);
+        final DisplayData wpdData = getDisplayDataOrCreate(DEFAULT_DISPLAY);
         out.startTag(null, tag);
         out.attribute(null, "id", Integer.toString(wallpaper.wallpaperId));
         out.attribute(null, "width", Integer.toString(wpdData.mWidth));
@@ -2755,10 +2825,10 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                     Slog.i(TAG, "No static wallpaper imagery; defaults will be shown");
                 }
             }
+            initializeFallbackWallpaper();
         }
         boolean success = false;
-        final WallpaperData.DisplayData wpdData = getDisplayDataOrCreate(wallpaper,
-                DEFAULT_DISPLAY);
+        final DisplayData wpdData = getDisplayDataOrCreate(DEFAULT_DISPLAY);
         try {
             stream = new FileInputStream(file);
             XmlPullParser parser = Xml.newPullParser();
@@ -2845,8 +2915,19 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
         }
     }
 
+    private void initializeFallbackWallpaper() {
+        if (mFallbackWallpaper == null) {
+            if (DEBUG) Slog.d(TAG, "Initialize fallback wallpaper");
+            mFallbackWallpaper = new WallpaperData(
+                    UserHandle.USER_SYSTEM, WALLPAPER, WALLPAPER_CROP);
+            mFallbackWallpaper.allowBackup = false;
+            mFallbackWallpaper.wallpaperId = makeWallpaperIdLocked();
+            bindWallpaperComponentLocked(mImageWallpaper, true, false, mFallbackWallpaper, null);
+        }
+    }
+
     private void ensureSaneWallpaperData(WallpaperData wallpaper, int displayId) {
-        final WallpaperData.DisplayData size = getDisplayDataOrCreate(wallpaper, displayId);
+        final DisplayData size = getDisplayDataOrCreate(displayId);
 
         if (displayId == DEFAULT_DISPLAY) {
             // crop, if not previously specified
@@ -2869,7 +2950,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
             wallpaper.wallpaperId = makeWallpaperIdLocked();
         }
 
-        final WallpaperData.DisplayData wpData = getDisplayDataOrCreate(wallpaper, DEFAULT_DISPLAY);
+        final DisplayData wpData = getDisplayDataOrCreate(DEFAULT_DISPLAY);
 
         if (!keepDimensionHints) {
             wpData.mWidth = Integer.parseInt(parser.getAttributeValue(null, "width"));
@@ -2963,7 +3044,7 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
     }
 
     // Restore the named resource bitmap to both source + crop files
-    boolean restoreNamedResourceLocked(WallpaperData wallpaper) {
+    private boolean restoreNamedResourceLocked(WallpaperData wallpaper) {
         if (wallpaper.name.length() > 4 && "res:".equals(wallpaper.name.substring(0, 4))) {
             String resName = wallpaper.name.substring(4);
 
@@ -3048,8 +3129,9 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
             for (int i = 0; i < mWallpaperMap.size(); i++) {
                 WallpaperData wallpaper = mWallpaperMap.valueAt(i);
                 pw.print(" User "); pw.print(wallpaper.userId);
-                    pw.print(": id="); pw.println(wallpaper.wallpaperId);
-                forEachDisplayData(wallpaper, wpSize -> {
+                pw.print(": id="); pw.println(wallpaper.wallpaperId);
+                pw.println(" Display state:");
+                forEachDisplayData(wpSize -> {
                     pw.print("  displayId=");
                     pw.println(wpSize.mDisplayId);
                     pw.print("  mWidth=");
@@ -3072,11 +3154,11 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                         pw.println(conn.mInfo.getComponent());
                     }
                     conn.forEachDisplayConnector(connector -> {
-                        pw.print("    mDisplayId=");
+                        pw.print("     mDisplayId=");
                         pw.println(connector.mDisplayId);
-                        pw.print("    mToken=");
+                        pw.print("     mToken=");
                         pw.println(connector.mToken);
-                        pw.print("    mEngine=");
+                        pw.print("     mEngine=");
                         pw.println(connector.mEngine);
                     });
                     pw.print("    mService=");
@@ -3090,18 +3172,38 @@ public class WallpaperManagerService extends IWallpaperManager.Stub
                 WallpaperData wallpaper = mLockWallpaperMap.valueAt(i);
                 pw.print(" User "); pw.print(wallpaper.userId);
                 pw.print(": id="); pw.println(wallpaper.wallpaperId);
-                forEachDisplayData(wallpaper, wpSize -> {
-                    pw.print("  displayId=");
-                    pw.println(wpSize.mDisplayId);
-                    pw.print("  mWidth="); pw.print(wpSize.mWidth);
-                    pw.print("  mHeight="); pw.println(wpSize.mHeight);
-                    pw.print("  mPadding="); pw.println(wpSize.mPadding);
-                });
                 pw.print("  mCropHint="); pw.println(wallpaper.cropHint);
                 pw.print("  mName=");  pw.println(wallpaper.name);
                 pw.print("  mAllowBackup="); pw.println(wallpaper.allowBackup);
             }
-
+            pw.println("Fallback wallpaper state:");
+            pw.print(" User "); pw.print(mFallbackWallpaper.userId);
+            pw.print(": id="); pw.println(mFallbackWallpaper.wallpaperId);
+            pw.print("  mCropHint="); pw.println(mFallbackWallpaper.cropHint);
+            pw.print("  mName=");  pw.println(mFallbackWallpaper.name);
+            pw.print("  mAllowBackup="); pw.println(mFallbackWallpaper.allowBackup);
+            if (mFallbackWallpaper.connection != null) {
+                WallpaperConnection conn = mFallbackWallpaper.connection;
+                pw.print("  Fallback Wallpaper connection ");
+                pw.print(conn);
+                pw.println(":");
+                if (conn.mInfo != null) {
+                    pw.print("    mInfo.component=");
+                    pw.println(conn.mInfo.getComponent());
+                }
+                conn.forEachDisplayConnector(connector -> {
+                    pw.print("     mDisplayId=");
+                    pw.println(connector.mDisplayId);
+                    pw.print("     mToken=");
+                    pw.println(connector.mToken);
+                    pw.print("     mEngine=");
+                    pw.println(connector.mEngine);
+                });
+                pw.print("    mService=");
+                pw.println(conn.mService);
+                pw.print("    mLastDiedTime=");
+                pw.println(mFallbackWallpaper.lastDiedTime - SystemClock.uptimeMillis());
+            }
         }
     }
 }