Changes to how we notify widget restore participants of new ids

As part of widget restore, we need to notify participants (hosts &
providers) of the mapping between ancestral and new widget ids.
Prior to this change, this was done at the end of system restore
and after each restore-at-install of unbundled apps.

There were two issues with this:
1) We would try to notify not-yet-installed participants at the end of
system restore and then *not* try again when they were installed.
2) We relied on PACKAGE_ADDED broadcasts to know which participants were
installed, but these are delivered asynchronously and not guaranteed
to be processed before the restoreFinished call.

After this change, we:
1) Only notify participants that are actually installed
2) Use receipt of the PACKAGE_ADDED / CHANGED broadcast to trigger
notification of any restore participants that are added or changed
*after* system restore completes.

2 is safe because by the time PackageManager sends the package
added / changed broadcasts, the app data restore has been completed,
and the app has been killed if needed.

Bug: 162057170
Test: Manual restore of Keep widget via cloud and d2d
Change-Id: I51dec33d09b62faba6d7c7daacd718a3c0682f7d

core/java/com/android/server/AppWidgetBackupBridge.java

@@ -47,9 +47,9 @@ public class AppWidgetBackupBridge {
                 : null;
     }
 
-    public static void restoreStarting(int userId) {
+    public static void systemRestoreStarting(int userId) {
         if (sAppWidgetService != null) {
-            sAppWidgetService.restoreStarting(userId);
+            sAppWidgetService.systemRestoreStarting(userId);
         }
     }
 
@@ -59,9 +59,9 @@ public class AppWidgetBackupBridge {
         }
     }
 
-    public static void restoreFinished(int userId) {
+    public static void systemRestoreFinished(int userId) {
         if (sAppWidgetService != null) {
-            sAppWidgetService.restoreFinished(userId);
+            sAppWidgetService.systemRestoreFinished(userId);
         }
     }
 }

core/java/com/android/server/WidgetBackupProvider.java

@@ -28,7 +28,7 @@ import java.util.List;
 public interface WidgetBackupProvider {
     public List<String> getWidgetParticipants(int userId);
     public byte[] getWidgetState(String packageName, int userId);
-    public void restoreStarting(int userId);
+    public void systemRestoreStarting(int userId);
     public void restoreWidgetState(String packageName, byte[] restoredState, int userId);
-    public void restoreFinished(int userId);
+    public void systemRestoreFinished(int userId);
 }

services/appwidget/java/com/android/server/appwidget/AppWidgetServiceImpl.java

@@ -409,6 +409,8 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
 
                 // If the set of providers has been modified, notify each active AppWidgetHost
                 scheduleNotifyGroupHostsForProvidersChangedLocked(userId);
+                // Possibly notify any new components of widget id changes
+                mBackupRestoreController.widgetComponentsChanged(userId);
             }
         }
     }
@@ -2471,8 +2473,8 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
     }
 
     @Override
-    public void restoreStarting(int userId) {
+    public void systemRestoreStarting(int userId) {
-        mBackupRestoreController.restoreStarting(userId);
+        mBackupRestoreController.systemRestoreStarting(userId);
     }
 
     @Override
@@ -2481,8 +2483,8 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
     }
 
     @Override
-    public void restoreFinished(int userId) {
+    public void systemRestoreFinished(int userId) {
-        mBackupRestoreController.restoreFinished(userId);
+        mBackupRestoreController.systemRestoreFinished(userId);
     }
 
     @SuppressWarnings("deprecation")
@@ -4272,6 +4274,9 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
         private final HashMap<Host, ArrayList<RestoreUpdateRecord>> mUpdatesByHost =
                 new HashMap<>();
 
+        @GuardedBy("mLock")
+        private boolean mHasSystemRestoreFinished;
+
         public List<String> getWidgetParticipants(int userId) {
             if (DEBUG) {
                 Slog.i(TAG, "Getting widget participants for user: " + userId);
@@ -4375,12 +4380,13 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
             return stream.toByteArray();
         }
 
-        public void restoreStarting(int userId) {
+        public void systemRestoreStarting(int userId) {
             if (DEBUG) {
-                Slog.i(TAG, "Restore starting for user: " + userId);
+                Slog.i(TAG, "System restore starting for user: " + userId);
             }
 
             synchronized (mLock) {
+                mHasSystemRestoreFinished = false;
                 // We're starting a new "system" restore operation, so any widget restore
                 // state that we see from here on is intended to replace the current
                 // widget configuration of any/all of the affected apps.
@@ -4542,22 +4548,52 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
             }
         }
 
-        // Called once following the conclusion of a restore operation.  This is when we
+        // Called once following the conclusion of a system restore operation.  This is when we
         // send out updates to apps involved in widget-state restore telling them about
-        // the new widget ID space.
+        // the new widget ID space.  Apps that are not yet installed will be notifed when they are.
-        public void restoreFinished(int userId) {
+        public void systemRestoreFinished(int userId) {
             if (DEBUG) {
-                Slog.i(TAG, "restoreFinished for " + userId);
+                Slog.i(TAG, "systemRestoreFinished for " + userId);
+            }
+            synchronized (mLock) {
+                mHasSystemRestoreFinished = true;
+                maybeSendWidgetRestoreBroadcastsLocked(userId);
+            }
+        }
+
+        // Called when widget components (hosts or providers) are added or changed.  If system
+        // restore has completed, we use this opportunity to tell the apps to update to the new
+        // widget ID space.  If system restore is still in progress, we delay the updates until
+        // the end, to allow all participants to restore their state before updating widget IDs.
+        public void widgetComponentsChanged(int userId) {
+            synchronized (mLock) {
+                if (mHasSystemRestoreFinished) {
+                    maybeSendWidgetRestoreBroadcastsLocked(userId);
+                }
+            }
+        }
+
+        // Called following the conclusion of a restore operation and when widget components
+        // are added or changed.  This is when we send out updates to apps involved in widget-state
+        // restore telling them about the new widget ID space.
+        @GuardedBy("mLock")
+        private void maybeSendWidgetRestoreBroadcastsLocked(int userId) {
+            if (DEBUG) {
+                Slog.i(TAG, "maybeSendWidgetRestoreBroadcasts for " + userId);
             }
 
             final UserHandle userHandle = new UserHandle(userId);
-            synchronized (mLock) {
             // Build the providers' broadcasts and send them off
             Set<Map.Entry<Provider, ArrayList<RestoreUpdateRecord>>> providerEntries
                     = mUpdatesByProvider.entrySet();
             for (Map.Entry<Provider, ArrayList<RestoreUpdateRecord>> e : providerEntries) {
                 // For each provider there's a list of affected IDs
                 Provider provider = e.getKey();
+                if (provider.zombie) {
+                    // Provider not installed, we can't send them broadcasts yet.
+                    // We'll be called again when the provider is installed.
+                    continue;
+                }
                 ArrayList<RestoreUpdateRecord> updates = e.getValue();
                 final int pending = countPendingUpdates(updates);
                 if (DEBUG) {
@@ -4621,7 +4657,6 @@ class AppWidgetServiceImpl extends IAppWidgetService.Stub implements WidgetBacku
                 }
             }
         }
-        }
 
         private Provider findProviderLocked(ComponentName componentName, int userId) {
             final int providerCount = mProviders.size();

services/backup/java/com/android/server/backup/restore/PerformUnifiedRestoreTask.java

@@ -381,7 +381,7 @@ public class PerformUnifiedRestoreTask implements BackupRestoreTask {
 
         // If we're starting a full-system restore, set up to begin widget ID remapping
         if (mIsSystemRestore) {
-            AppWidgetBackupBridge.restoreStarting(mUserId);
+            AppWidgetBackupBridge.systemRestoreStarting(mUserId);
         }
 
         try {
@@ -1133,8 +1133,10 @@ public class PerformUnifiedRestoreTask implements BackupRestoreTask {
                     restoreAgentTimeoutMillis);
         }
 
+        if (mIsSystemRestore) {
             // Kick off any work that may be needed regarding app widget restores
-        AppWidgetBackupBridge.restoreFinished(mUserId);
+            AppWidgetBackupBridge.systemRestoreFinished(mUserId);
+        }
 
         // If this was a full-system restore, record the ancestral
         // dataset information