Moving business logic preconditions to the beginning of the function.

2017-09-23 11:57:29 +08:00
parent 158a7a881d
commit e70dd18734
3 changed files with 7 additions and 6 deletions
--- a/contracts/token/BurnableToken.sol
+++ b/contracts/token/BurnableToken.sol
@ -16,6 +16,9 @@ contract BurnableToken is StandardToken {
     */
    function burn(uint256 _value) public {
        require(_value > 0);
+        require(_value <= balances[msg.sender]);
+        // no need to require value <= totalSupply, since that would imply the
+        // sender's balance is greater than the totalSupply, which *should* be an assertion failure

        address burner = msg.sender;
        balances[burner] = balances[burner].sub(_value);