Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

OUSD Better Burn Mint #1680

Draft
wants to merge 1 commit into
base: master
Choose a base branch
from
Draft

OUSD Better Burn Mint #1680

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
104 changes: 36 additions & 68 deletions contracts/contracts/token/OUSD.sol
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -343,37 +343,16 @@ contract OUSD is Initializable, InitializableERC20Detailed, Governable {
* @dev Mints new tokens, increasing totalSupply.
*/
function mint(address _account, uint256 _amount) external onlyVault {
_mint(_account, _amount);
}

/**
* @dev Creates `_amount` tokens and assigns them to `_account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements
*
* - `to` cannot be the zero address.
*/
function _mint(address _account, uint256 _amount) internal nonReentrant {
require(_account != address(0), "Mint to the zero address");

bool isNonRebasingAccount = _isNonRebasingAccount(_account);

uint256 creditAmount = _amount.mulTruncate(_creditsPerToken(_account));
_creditBalances[_account] = _creditBalances[_account].add(creditAmount);

// If the account is non rebasing and doesn't have a set creditsPerToken
// then set it i.e. this is a mint from a fresh contract
if (isNonRebasingAccount) {
nonRebasingSupply = nonRebasingSupply.add(_amount);
} else {
_rebasingCredits = _rebasingCredits.add(creditAmount);
if (_amount == 0) {
return;
}

_totalSupply = _totalSupply.add(_amount);
uint256 oldBalance = balanceOf(_account);
uint256 newBalance = oldBalance + _amount;

_setBalance(_account, newBalance, oldBalance);
_totalSupply += _amount;
require(_totalSupply < MAX_SUPPLY, "Max supply");

emit Transfer(address(0), _account, _amount);
Expand All @@ -383,54 +362,43 @@ contract OUSD is Initializable, InitializableERC20Detailed, Governable {
* @dev Burns tokens, decreasing totalSupply.
*/
function burn(address account, uint256 amount) external onlyVault {
_burn(account, amount);
}

/**
* @dev Destroys `_amount` tokens from `_account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements
*
* - `_account` cannot be the zero address.
* - `_account` must have at least `_amount` tokens.
*/
function _burn(address _account, uint256 _amount) internal nonReentrant {
require(_account != address(0), "Burn from the zero address");
if (_amount == 0) {
require(account != address(0), "Burn from the zero address");
if (amount == 0) {
return;
}

bool isNonRebasingAccount = _isNonRebasingAccount(_account);
uint256 creditAmount = _amount.mulTruncate(_creditsPerToken(_account));
uint256 currentCredits = _creditBalances[_account];

// Remove the credits, burning rounding errors
if (
currentCredits == creditAmount || currentCredits - 1 == creditAmount
) {
// Handle dust from rounding
_creditBalances[_account] = 0;
} else if (currentCredits > creditAmount) {
_creditBalances[_account] = _creditBalances[_account].sub(
creditAmount
);
} else {
revert("Remove exceeds balance");
}
uint256 oldBalance = balanceOf(account);
require(oldBalance >= amount, "Remove exceeds balance");
uint256 newBalance = oldBalance - amount;

// Remove from the credit tallies and non-rebasing supply
_setBalance(account, newBalance, oldBalance);
_totalSupply -= amount;

emit Transfer(account, address(0), amount);
}

/** @dev Sets an account's balanace to a specified amount
* @param _account The account which will be adjusted
* @param _newBalance The new balance to set to
* @param _oldBalance The previous new balance we are changing from
*/
function _setBalance(
address _account,
uint256 _newBalance,
uint256 _oldBalance
) internal {
bool isNonRebasingAccount = _isNonRebasingAccount(_account);
if (isNonRebasingAccount) {
nonRebasingSupply = nonRebasingSupply.sub(_amount);
nonRebasingCreditsPerToken[_account] = 1e18;
_creditBalances[_account] = _newBalance;
nonRebasingSupply = nonRebasingSupply + _newBalance - _oldBalance;
} else {
_rebasingCredits = _rebasingCredits.sub(creditAmount);
uint256 oldCredits = _creditBalances[_account];
uint256 newCredits = (_newBalance * _rebasingCreditsPerToken) /
1e18;
_creditBalances[_account] = newCredits;
_rebasingCredits = _rebasingCredits + newCredits - oldCredits;
}

_totalSupply = _totalSupply.sub(_amount);

emit Transfer(_account, address(0), _amount);
}

/**
Expand Down