sync: Verify PasswdSafeProvider query sort order

Ensure the user's sort order is not passed to the database query.  Create
QuerySortOrder class to encapsulate validation of the order and to save the
fixed string to pass to the query.

sync/src/main/java/com/jefftharris/passwdsafe/sync/PasswdSafeProvider.java

@@ -322,24 +322,21 @@ public Cursor query(@NonNull Uri uri,
                         String[] projection,
                         String selection,
                         String[] selectionArgs,
-                        String sortOrder)
+                        final String userSortOrder)
     {
         PasswdSafeUtil.dbginfo(TAG, "query uri: %s", uri);
 
         boolean selectionValid = (selection == null);
         boolean selectionArgsValid = (selectionArgs == null);
-        boolean sortOrderValid = (sortOrder == null);
+        final var sortOrder = new QuerySortOrder(userSortOrder);
 
         final SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
         switch (PasswdSafeContract.MATCHER.match(uri)) {
         case PasswdSafeContract.MATCH_PROVIDERS: {
             qb.setTables(SyncDb.DB_TABLE_PROVIDERS);
             qb.setProjectionMap(PROVIDERS_MAP);
 
-            if (PasswdSafeContract.Providers.PROVIDER_SORT_ORDER.equals(
-                    sortOrder)) {
-                sortOrderValid = true;
-            }
+            sortOrder.check(PasswdSafeContract.Providers.PROVIDER_SORT_ORDER);
             break;
         }
         case PasswdSafeContract.MATCH_PROVIDER: {
@@ -366,9 +363,7 @@ public Cursor query(@NonNull Uri uri,
 
             selectionArgs =
                     new String[] { PasswdSafeContract.Providers.getIdStr(uri) };
-            if (PasswdSafeContract.Files.TITLE_SORT_ORDER.equals(sortOrder)) {
-                sortOrderValid = true;
-            }
+            sortOrder.check(PasswdSafeContract.Files.TITLE_SORT_ORDER);
             break;
         }
         case PasswdSafeContract.MATCH_PROVIDER_FILE: {
@@ -382,9 +377,7 @@ public Cursor query(@NonNull Uri uri,
         case PasswdSafeContract.MATCH_SYNC_LOGS: {
             qb.setTables(SyncDb.DB_TABLE_SYNC_LOGS);
             qb.setProjectionMap(SYNC_LOGS_MAP);
-            if (PasswdSafeContract.SyncLogs.START_SORT_ORDER.equals(sortOrder)) {
-                sortOrderValid = true;
-            }
+            sortOrder.check(PasswdSafeContract.SyncLogs.START_SORT_ORDER);
             if (PasswdSafeContract.SyncLogs.DEFAULT_SELECTION.equals(
                         selection)) {
                 selectionValid = true;
@@ -439,13 +432,13 @@ public Cursor query(@NonNull Uri uri,
         if (!selectionArgsValid) {
             throw new IllegalArgumentException("selectionArgs not supported");
         }
-        if (!sortOrderValid) {
+        if (!sortOrder.itsIsValid) {
             throw new IllegalArgumentException("sortOrder not supported");
         }
 
         try {
             Cursor c = SyncDb.queryDb(qb, projection, selection, selectionArgs,
-                                      sortOrder);
+                                      sortOrder.itsSortOrder);
             Context ctx = getContext();
             if ((c != null) && (ctx != null)) {
                 c.setNotificationUri(ctx.getContentResolver(),
@@ -834,4 +827,34 @@ protected Void doInBackground(Void... voids)
             return null;
         }
     }
+
+    /**
+     * Checker for a valid query sort order
+     */
+    private static class QuerySortOrder
+    {
+        private final String itsUserSortOrder;
+        private boolean itsIsValid;
+        private String itsSortOrder = null;
+
+        /**
+         * Constructor
+         */
+        private QuerySortOrder(@Nullable String userSortOrder)
+        {
+            itsUserSortOrder = userSortOrder;
+            itsIsValid = (itsUserSortOrder == null);
+        }
+
+        /**
+         * Check whether a known valid sort order matches the user's sort order
+         */
+        private void check(@NonNull String checkSort)
+        {
+            if (!itsIsValid && checkSort.equals(itsUserSortOrder)) {
+                itsIsValid = true;
+                itsSortOrder = checkSort;
+            }
+        }
+    }
 }