From c23f8103debc40087c8e10d4e41c09b69d4322a1 Mon Sep 17 00:00:00 2001 From: Hendrik Hofstadt Date: Thu, 6 Aug 2020 16:17:41 +0200 Subject: [PATCH] Fix wrapped asset proxy --- ethereum/contracts/WrappedAsset.sol | 276 +++++++++++++++++++++++++++- 1 file changed, 272 insertions(+), 4 deletions(-) diff --git a/ethereum/contracts/WrappedAsset.sol b/ethereum/contracts/WrappedAsset.sol index 43b69142f..3ca92823b 100644 --- a/ethereum/contracts/WrappedAsset.sol +++ b/ethereum/contracts/WrappedAsset.sol @@ -2,9 +2,12 @@ // SPDX-License-Identifier: Apache 2 pragma solidity ^0.6.0; -import "@openzeppelin/contracts/token/ERC20/ERC20.sol"; +import "@openzeppelin/contracts/token/ERC20/IERC20.sol"; +import "@openzeppelin/contracts/math/SafeMath.sol"; +import "@openzeppelin/contracts/utils/Address.sol"; +import "@openzeppelin/contracts/GSN/Context.sol"; -contract WrappedAsset is ERC20("Wormhole Wrapped Asset", "WASSET") { +contract WrappedAsset is IERC20, Context { uint8 public assetChain; bytes32 public assetAddress; bool public initialized; @@ -17,17 +20,282 @@ contract WrappedAsset is ERC20("Wormhole Wrapped Asset", "WASSET") { assetAddress = _assetAddress; bridge = msg.sender; initialized = true; + + _name = "Wormhole Wrapped"; + _symbol = "WWT"; + _decimals = 18; } function mint(address account, uint256 amount) external { require(msg.sender == bridge, "mint can only be called by the bridge"); - super._mint(account, amount); + _mint(account, amount); } function burn(address account, uint256 amount) external { require(msg.sender == bridge, "burn can only be called by the bridge"); - super._burn(account, amount); + _burn(account, amount); } + + // Taken from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol + // Licensed under MIT + + using SafeMath for uint256; + using Address for address; + + mapping(address => uint256) private _balances; + + mapping(address => mapping(address => uint256)) private _allowances; + + uint256 private _totalSupply; + + string private _name; + string private _symbol; + uint8 private _decimals = 18; + + /** + * @dev Returns the name of the token. + */ + function name() public view returns (string memory) { + return _name; + } + + /** + * @dev Returns the symbol of the token, usually a shorter version of the + * name. + */ + function symbol() public view returns (string memory) { + return _symbol; + } + + /** + * @dev Returns the number of decimals used to get its user representation. + * For example, if `decimals` equals `2`, a balance of `505` tokens should + * be displayed to a user as `5,05` (`505 / 10 ** 2`). + * + * Tokens usually opt for a value of 18, imitating the relationship between + * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is + * called. + * + * NOTE: This information is only used for _display_ purposes: it in + * no way affects any of the arithmetic of the contract, including + * {IERC20-balanceOf} and {IERC20-transfer}. + */ + function decimals() public view returns (uint8) { + return _decimals; + } + + /** + * @dev See {IERC20-totalSupply}. + */ + function totalSupply() public view override returns (uint256) { + return _totalSupply; + } + + /** + * @dev See {IERC20-balanceOf}. + */ + function balanceOf(address account) public view override returns (uint256) { + return _balances[account]; + } + + /** + * @dev See {IERC20-transfer}. + * + * Requirements: + * + * - `recipient` cannot be the zero address. + * - the caller must have a balance of at least `amount`. + */ + function transfer(address recipient, uint256 amount) public virtual override returns (bool) { + _transfer(_msgSender(), recipient, amount); + return true; + } + + /** + * @dev See {IERC20-allowance}. + */ + function allowance(address owner, address spender) public view virtual override returns (uint256) { + return _allowances[owner][spender]; + } + + /** + * @dev See {IERC20-approve}. + * + * Requirements: + * + * - `spender` cannot be the zero address. + */ + function approve(address spender, uint256 amount) public virtual override returns (bool) { + _approve(_msgSender(), spender, amount); + return true; + } + + /** + * @dev See {IERC20-transferFrom}. + * + * Emits an {Approval} event indicating the updated allowance. This is not + * required by the EIP. See the note at the beginning of {ERC20}; + * + * Requirements: + * - `sender` and `recipient` cannot be the zero address. + * - `sender` must have a balance of at least `amount`. + * - the caller must have allowance for ``sender``'s tokens of at least + * `amount`. + */ + function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) { + _transfer(sender, recipient, amount); + _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance")); + return true; + } + + /** + * @dev Atomically increases the allowance granted to `spender` by the caller. + * + * This is an alternative to {approve} that can be used as a mitigation for + * problems described in {IERC20-approve}. + * + * Emits an {Approval} event indicating the updated allowance. + * + * Requirements: + * + * - `spender` cannot be the zero address. + */ + function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) { + _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue)); + return true; + } + + /** + * @dev Atomically decreases the allowance granted to `spender` by the caller. + * + * This is an alternative to {approve} that can be used as a mitigation for + * problems described in {IERC20-approve}. + * + * Emits an {Approval} event indicating the updated allowance. + * + * Requirements: + * + * - `spender` cannot be the zero address. + * - `spender` must have allowance for the caller of at least + * `subtractedValue`. + */ + function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) { + _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero")); + return true; + } + + /** + * @dev Moves tokens `amount` from `sender` to `recipient`. + * + * This is internal function is equivalent to {transfer}, and can be used to + * e.g. implement automatic token fees, slashing mechanisms, etc. + * + * Emits a {Transfer} event. + * + * Requirements: + * + * - `sender` cannot be the zero address. + * - `recipient` cannot be the zero address. + * - `sender` must have a balance of at least `amount`. + */ + function _transfer(address sender, address recipient, uint256 amount) internal virtual { + require(sender != address(0), "ERC20: transfer from the zero address"); + require(recipient != address(0), "ERC20: transfer to the zero address"); + + _beforeTokenTransfer(sender, recipient, amount); + + _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance"); + _balances[recipient] = _balances[recipient].add(amount); + emit Transfer(sender, recipient, 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 virtual { + require(account != address(0), "ERC20: mint to the zero address"); + + _beforeTokenTransfer(address(0), account, amount); + + _totalSupply = _totalSupply.add(amount); + _balances[account] = _balances[account].add(amount); + emit Transfer(address(0), 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 virtual { + require(account != address(0), "ERC20: burn from the zero address"); + + _beforeTokenTransfer(account, address(0), amount); + + _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance"); + _totalSupply = _totalSupply.sub(amount); + emit Transfer(account, address(0), amount); + } + + /** + * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens. + * + * This is internal function is equivalent to `approve`, and can be used to + * e.g. set automatic allowances for certain subsystems, etc. + * + * Emits an {Approval} event. + * + * Requirements: + * + * - `owner` cannot be the zero address. + * - `spender` cannot be the zero address. + */ + function _approve(address owner, address spender, uint256 amount) internal virtual { + require(owner != address(0), "ERC20: approve from the zero address"); + require(spender != address(0), "ERC20: approve to the zero address"); + + _allowances[owner][spender] = amount; + emit Approval(owner, spender, amount); + } + + /** + * @dev Sets {decimals} to a value other than the default one of 18. + * + * WARNING: This function should only be called from the constructor. Most + * applications that interact with token contracts will not expect + * {decimals} to ever change, and may work incorrectly if it does. + */ + function _setupDecimals(uint8 decimals_) internal { + _decimals = decimals_; + } + + /** + * @dev Hook that is called before any transfer of tokens. This includes + * minting and burning. + * + * Calling conditions: + * + * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens + * will be to transferred to `to`. + * - when `from` is zero, `amount` tokens will be minted for `to`. + * - when `to` is zero, `amount` of ``from``'s tokens will be burned. + * - `from` and `to` are never both zero. + * + * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks]. + */ + function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {} }