skip backup if launcher is in a bad state

Bug: 13153542
Change-Id: I4312ebd200e8e652ef841f54301981c2a486b726

src/com/android/launcher3/LauncherBackupHelper.java

@@ -50,9 +50,7 @@ import android.util.Base64;
 import android.util.Log;
 
 import java.io.ByteArrayOutputStream;
-import java.io.File;
 import java.io.FileInputStream;
-import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.net.URISyntaxException;
@@ -188,16 +186,20 @@ public class LauncherBackupHelper implements BackupHelper {
         Log.v(TAG, "lastBackupTime = " + lastBackupTime);
 
         ArrayList<Key> keys = new ArrayList<Key>();
-        try {
-            backupFavorites(in, data, out, keys);
-            backupScreens(in, data, out, keys);
-            backupIcons(in, data, out, keys);
-            backupWidgets(in, data, out, keys);
-        } catch (IOException e) {
-            Log.e(TAG, "launcher backup has failed", e);
+        if (launcherIsReady()) {
+            try {
+                backupFavorites(in, data, out, keys);
+                backupScreens(in, data, out, keys);
+                backupIcons(in, data, out, keys);
+                backupWidgets(in, data, out, keys);
+            } catch (IOException e) {
+                Log.e(TAG, "launcher backup has failed", e);
+            }
+            out.key = keys.toArray(new BackupProtos.Key[keys.size()]);
+        } else {
+            out = in;
         }
 
-        out.key = keys.toArray(new BackupProtos.Key[keys.size()]);
         writeJournal(newState, out);
         Log.v(TAG, "onBackup: wrote " + out.bytes + "b in " + out.rows + " rows.");
     }
@@ -1129,6 +1131,26 @@ public class LauncherBackupHelper implements BackupHelper {
         return mIconCache != null;
     }
 
+
+   // check if the launcher is in a state to support backup
+    private boolean launcherIsReady() {
+        ContentResolver cr = mContext.getContentResolver();
+        Cursor cursor = cr.query(Favorites.CONTENT_URI, FAVORITE_PROJECTION, null, null, null);
+        if (cursor == null) {
+            // launcher data has been wiped, do nothing
+            return false;
+        }
+        cursor.close();
+
+        if (!initializeIconCache()) {
+            // launcher services are unavailable, try again later
+            dataChanged();
+            return false;
+        }
+
+        return true;
+    }
+
     private class KeyParsingException extends Throwable {
         private KeyParsingException(Throwable cause) {
             super(cause);