Check balance for lock and account transactions

src/ercoin_tx.erl

@@ -24,7 +24,9 @@
     serialize/1,
     unpack_binary/2,
     handle_bin/2,
-    valid_since/1]).
+    required_balance/2,
+    valid_since/1,
+    value/1]).
 
 -spec valid_since(tx()) -> block_height() | none.
 valid_since(#transfer_tx{valid_since=ValidSince}) ->
@@ -48,6 +50,16 @@ from(#vote_tx{address=Address}) ->
 from(#burn_tx{address=Address}) ->
     Address.
 
+-spec value(tx()) -> non_neg_integer().
+value(Tx) when is_record(Tx, burn_tx) orelse is_record(Tx, transfer_tx) ->
+    get_value(value, Tx);
+value(_) ->
+    0.
+
+-spec required_balance(tx(), data()) -> non_neg_integer().
+required_balance(Tx, Data) ->
+    value(Tx) + ercoin_fee:total(Tx, Data).
+
 -spec serialize(tx()) -> binary().
 serialize(
   #transfer_tx{
@@ -165,8 +177,13 @@ error_code(Tx, Data=#data{height=Height, epoch_length=EpochLength}) ->
                     case ercoin_account:get(ercoin_tx:from(Tx), Data) of
                         none ->
                             ?NOT_FOUND;
-                        From ->
-                            error_code_1(Tx, Data, From)
+                        From=#account{balance=Balance} ->
+                            case Balance >= ercoin_tx:required_balance(Tx, Data) of
+                                true ->
+                                    error_code_1(Tx, Data, From);
+                                false ->
+                                    ?INSUFFICIENT_FUNDS
+                            end
                     end
             end;
         _ ->
@@ -174,7 +191,7 @@ error_code(Tx, Data=#data{height=Height, epoch_length=EpochLength}) ->
     end.
 
 -spec error_code_1(tx(), data(), account() | none) -> error_code().
-error_code_1(Tx=#transfer_tx{to=To, value=Value}, Data, #account{locked_until=LockedUntil, balance=Balance}) ->
+error_code_1(Tx=#transfer_tx{to=To}, Data, #account{locked_until=LockedUntil}) ->
     case in_fresh_txs(Tx, Data) of
         false ->
             case ercoin_account:get(To, Data) of
@@ -183,12 +200,7 @@ error_code_1(Tx=#transfer_tx{to=To, value=Value}, Data, #account{locked_until=Lo
                 #account{} ->
                     case LockedUntil of
                         none ->
-                            case Balance < ercoin_fee:total(Tx, Data) + Value of
-                                false ->
-                                    ?OK;
-                                true ->
-                                    ?INSUFFICIENT_FUNDS
-                            end;
+                            ?OK;
                         _ ->
                             ?FORBIDDEN
                     end
@@ -245,17 +257,12 @@ error_code_1(Tx=#vote_tx{address=Address}, Data=#data{validators=Validators, fut
         _ ->
             ?ALREADY_EXECUTED
     end;
-error_code_1(Tx=#burn_tx{value=Value}, Data, #account{balance=Balance, locked_until=LockedUntil}) ->
+error_code_1(Tx=#burn_tx{}, Data, #account{locked_until=LockedUntil}) ->
     case in_fresh_txs(Tx, Data) of
         false ->
             case LockedUntil of
                 none ->
-                    case Balance < ercoin_fee:total(Tx, Data) + Value of
-                        false ->
-                            ?OK;
-                        true ->
-                            ?INSUFFICIENT_FUNDS
-                    end;
+                    ?OK;
                 _ ->
                     ?FORBIDDEN
             end;

test/ercoin_tx_gen.erl

@@ -164,17 +164,7 @@ data_sks_and_lock_tx() ->
 -spec make_sufficient_balance(data(), tx()) -> data().
 make_sufficient_balance(Data, Tx) ->
     Account = ercoin_account:get(ercoin_tx:from(Tx), Data),
-    Fee = ercoin_fee:total(Tx, Data),
-    MinBalance =
-        case Tx of
-            #transfer_tx{value=Value} ->
-                Fee + Value;
-            #burn_tx{value=Value} ->
-                Fee + Value;
-            _ ->
-                Fee
-        end,
-    NewAccount = Account#account{balance=max(MinBalance, Account#account.balance)},
+    NewAccount = Account#account{balance=max(ercoin_tx:required_balance(Tx, Data), Account#account.balance)},
     ercoin_account:put(NewAccount, Data).
 
 transfer_tx({Data, SKs}, From, To) ->
@@ -292,20 +282,20 @@ data_with_invalid_tx_bin() ->
               TxBin = ercoin_tx:serialize(Tx),
               {Data, <<Prefix/binary, TxBin/binary, Suffix/binary>>}
           end),
-       %% Insufficient balance for transfer/burn.
+       %% Insufficient balance.
        ?LET(
-          {{{Data, SKs}, Tx},
+          {{{Data, _}, Tx},
            LackingFunds},
-          {oneof(
-             [fun data_sks_and_transfer_tx/0,
-              fun data_sks_and_burn_tx/0]),
+          {?SUCHTHAT(
+              {_, Tx},
+              data_sks_and_tx(),
+              not is_record(Tx, vote_tx)),
            pos_integer()},
           begin
               Account = ercoin_account:get(ercoin_tx:from(Tx), Data),
-              InvalidValue = max(0, Account#account.balance - ercoin_fee:total(Tx, Data) + LackingFunds),
-              InvalidTx =
-                  sign_tx(set_value(value, InvalidValue, Tx), SKs),
-              {Data, ercoin_tx:serialize(InvalidTx)}
+              InvalidAccount = Account#account{balance=max(0, ercoin_tx:required_balance(Tx, Data) - LackingFunds)},
+              {ercoin_account:put(InvalidAccount, Data),
+               ercoin_tx:serialize(Tx)}
           end),
        %% Bad signature.
        ?LET(

test/ercoin_tx_tests.erl

@@ -163,3 +163,9 @@ prop_non_burn_tx_does_not_change_money_supply() ->
        ?IMPLIES(
           not is_record(Tx, burn_tx),
           ercoin_data:money_supply(ercoin_tx:apply(Tx, Data)) =:= ercoin_data:money_supply(Data))).
+
+prop_tx_does_not_increase_money_supply() ->
+    ?FORALL(
+       {Data, Tx},
+       data_with_tx(),
+       ercoin_data:money_supply(ercoin_tx:apply(Tx, Data)) =< ercoin_data:money_supply(Data)).