tabledb work

veilid-flutter/lib/veilid_table_db.dart

@@ -25,11 +25,11 @@ abstract class VeilidTableDBTransaction {
 
 abstract class VeilidTableDB {
   int getColumnCount();
-  List<Uint8List> getKeys(int col);
+  Future<List<Uint8List>> getKeys(int col);
   VeilidTableDBTransaction transact();
   Future<void> store(int col, Uint8List key, Uint8List value);
   Future<Uint8List?> load(int col, Uint8List key);
-  Future<bool> delete(int col, Uint8List key);
+  Future<Uint8List?> delete(int col, Uint8List key);
 
   Future<void> storeJson(int col, Uint8List key, Object? object,
       {Object? Function(Object? nonEncodable)? toEncodable}) {
@@ -56,4 +56,18 @@ abstract class VeilidTableDB {
       {Object? Function(Object? key, Object? value)? reviver}) {
     return loadJson(col, utf8.encoder.convert(key), reviver: reviver);
   }
+
+  Future<Object?> deleteJson(int col, Uint8List key,
+      {Object? Function(Object? key, Object? value)? reviver}) async {
+    var s = await delete(col, key);
+    if (s == null) {
+      return null;
+    }
+    return jsonDecode(utf8.decode(s, allowMalformed: false), reviver: reviver);
+  }
+
+  Future<Object?> deleteStringJson(int col, String key,
+      {Object? Function(Object? key, Object? value)? reviver}) {
+    return deleteJson(col, utf8.encoder.convert(key), reviver: reviver);
+  }
 }