文件 1 的 1:USDEToken.sol
pragma solidity ^0.5.2;
interface IERC20 {
function transfer(address to, uint256 value) external returns (bool);
function approve(address spender, uint256 value) external returns (bool);
function transferFrom(address from, address to, uint256 value) external returns (bool);
function totalSupply() external view returns (uint256);
function balanceOf(address who) external view returns (uint256);
function allowance(address owner, address spender) external view returns (uint256);
event Transfer(address indexed from, address indexed to, uint256 value);
event Approval(address indexed owner, address indexed spender, uint256 value);
}
library SafeMath {
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b);
return c;
}
function div(uint256 a, uint256 b) internal pure returns (uint256) {
require(b > 0);
uint256 c = a / b;
return c;
}
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
require(b <= a);
uint256 c = a - b;
return c;
}
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a);
return c;
}
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
require(b != 0);
return a % b;
}
}
contract ERC20 is IERC20 {
using SafeMath for uint256;
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowed;
uint256 private _totalSupply;
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
function balanceOf(address owner) public view returns (uint256) {
return _balances[owner];
}
function allowance(address owner, address spender) public view returns (uint256) {
return _allowed[owner][spender];
}
function transfer(address to, uint256 value) public returns (bool) {
_transfer(msg.sender, to, value);
return true;
}
function approve(address spender, uint256 value) public returns (bool) {
_approve(msg.sender, spender, value);
return true;
}
function transferFrom(address from, address to, uint256 value) public returns (bool) {
_transfer(from, to, value);
_approve(from, msg.sender, _allowed[from][msg.sender].sub(value));
return true;
}
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
_approve(msg.sender, spender, _allowed[msg.sender][spender].add(addedValue));
return true;
}
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
_approve(msg.sender, spender, _allowed[msg.sender][spender].sub(subtractedValue));
return true;
}
function _transfer(address from, address to, uint256 value) internal {
require(to != address(0));
_balances[from] = _balances[from].sub(value);
_balances[to] = _balances[to].add(value);
emit Transfer(from, to, value);
}
function _mint(address account, uint256 value) internal {
require(account != address(0));
_totalSupply = _totalSupply.add(value);
_balances[account] = _balances[account].add(value);
emit Transfer(address(0), account, value);
}
function _burn(address account, uint256 value) internal {
require(account != address(0));
_totalSupply = _totalSupply.sub(value);
_balances[account] = _balances[account].sub(value);
emit Transfer(account, address(0), value);
}
function _approve(address owner, address spender, uint256 value) internal {
require(spender != address(0));
require(owner != address(0));
_allowed[owner][spender] = value;
emit Approval(owner, spender, value);
}
function _burnFrom(address account, uint256 value) internal {
_burn(account, value);
_approve(account, msg.sender, _allowed[account][msg.sender].sub(value));
}
}
library Roles {
struct Role {
mapping(address => bool) bearer;
}
function add(Role storage role, address account) internal {
require(account != address(0));
require(!has(role, account));
role.bearer[account] = true;
}
function remove(Role storage role, address account) internal {
require(account != address(0));
require(has(role, account));
role.bearer[account] = false;
}
function has(Role storage role, address account) internal view returns (bool) {
require(account != address(0));
return role.bearer[account];
}
}
contract PauserRole {
using Roles for Roles.Role;
event PauserAdded(address indexed account);
event PauserRemoved(address indexed account);
Roles.Role private _pausers;
constructor () internal {
_addPauser(msg.sender);
}
modifier onlyPauser() {
require(isPauser(msg.sender));
_;
}
function isPauser(address account) public view returns (bool) {
return _pausers.has(account);
}
function addPauser(address account) public onlyPauser {
_addPauser(account);
}
function renouncePauser() public {
_removePauser(msg.sender);
}
function _addPauser(address account) internal {
_pausers.add(account);
emit PauserAdded(account);
}
function _removePauser(address account) internal {
_pausers.remove(account);
emit PauserRemoved(account);
}
}
contract Pausable is PauserRole {
event Paused(address account);
event Unpaused(address account);
bool private _paused;
constructor () internal {
_paused = false;
}
function paused() public view returns (bool) {
return _paused;
}
modifier whenNotPaused() {
require(!_paused);
_;
}
modifier whenPaused() {
require(_paused);
_;
}
function pause() public onlyPauser whenNotPaused {
_paused = true;
emit Paused(msg.sender);
}
function unpause() public onlyPauser whenPaused {
_paused = false;
emit Unpaused(msg.sender);
}
}
contract PauseableToken is ERC20, Pausable {
function transfer(address to, uint256 value) public whenNotPaused returns (bool) {
return super.transfer(to, value);
}
function transferFrom(address from, address to, uint256 value) public whenNotPaused returns (bool) {
return super.transferFrom(from, to, value);
}
function approve(address spender, uint256 value) public whenNotPaused returns (bool) {
return super.approve(spender, value);
}
function increaseAllowance(address spender, uint addedValue) public whenNotPaused returns (bool success) {
return super.increaseAllowance(spender, addedValue);
}
function decreaseAllowance(address spender, uint subtractedValue) public whenNotPaused returns (bool success) {
return super.decreaseAllowance(spender, subtractedValue);
}
}
contract Ownable {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
constructor () internal {
_owner = msg.sender;
emit OwnershipTransferred(address(0), _owner);
}
function owner() public view returns (address) {
return _owner;
}
modifier onlyOwner() {
require(isOwner());
_;
}
function isOwner() public view returns (bool) {
return msg.sender == _owner;
}
function transferOwnership(address newOwner) public onlyOwner {
_transferOwnership(newOwner);
}
function _transferOwnership(address newOwner) internal {
require(newOwner != address(0));
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
contract USDEToken is PauseableToken, Ownable {
string private _name;
string private _symbol;
uint8 private _decimals;
constructor (string memory name, string memory symbol, uint8 decimals) public {
_name = name;
_symbol = symbol;
_decimals = decimals;
}
function name() public view returns (string memory) {
return _name;
}
function symbol() public view returns (string memory) {
return _symbol;
}
function decimals() public view returns (uint8) {
return _decimals;
}
function mint(address account, uint256 value) public onlyOwner {
_mint(account, value);
}
function burnFrom(address account, uint256 value) public onlyOwner {
_burnFrom(account, value);
}
function burn(address account, uint256 value) public onlyOwner {
_burn(account, value);
}
}