Contract Source Code:
File 1 of 1 : CfoCoin
// File: @openzeppelin/contracts/token/ERC20/IERC20.sol
pragma solidity ^0.5.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP. Does not include
* the optional functions; to access them see `ERC20Detailed`.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a `Transfer` event.
*/
function transfer(address recipient, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through `transferFrom`. This is
* zero by default.
*
* This value changes when `approve` or `transferFrom` are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* > Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an `Approval` event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a `Transfer` event.
*/
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to `approve`. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
// File: @openzeppelin/contracts/math/SafeMath.sol
pragma solidity ^0.5.0;
/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
require(b <= a, "SafeMath: subtraction overflow");
uint256 c = a - b;
return c;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0, "SafeMath: division by zero");
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
require(b != 0, "SafeMath: modulo by zero");
return a % b;
}
}
// File: @openzeppelin/contracts/token/ERC20/ERC20.sol
pragma solidity ^0.5.0;
/**
* @dev Implementation of the `IERC20` interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using `_mint`.
* For a generic mechanism see `ERC20Mintable`.
*
* *For a detailed writeup see our guide [How to implement supply
* mechanisms](https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226).*
*
* We have followed general OpenZeppelin guidelines: functions revert instead
* of returning `false` on failure. This behavior is nonetheless conventional
* and does not conflict with the expectations of ERC20 applications.
*
* Additionally, an `Approval` event is emitted on calls to `transferFrom`.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard `decreaseAllowance` and `increaseAllowance`
* functions have been added to mitigate the well-known issues around setting
* allowances. See `IERC20.approve`.
*/
contract ERC20 is IERC20 {
using SafeMath for uint256;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
/**
* @dev See `IERC20.totalSupply`.
*/
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
/**
* @dev See `IERC20.balanceOf`.
*/
function balanceOf(address account) public view 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 returns (bool) {
_transfer(msg.sender, recipient, amount);
return true;
}
/**
* @dev See `IERC20.allowance`.
*/
function allowance(address owner, address spender) public view returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See `IERC20.approve`.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 value) public returns (bool) {
_approve(msg.sender, spender, value);
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 `value`.
* - the caller must have allowance for `sender`'s tokens of at least
* `amount`.
*/
function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, msg.sender, _allowances[sender][msg.sender].sub(amount));
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 returns (bool) {
_approve(msg.sender, spender, _allowances[msg.sender][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 returns (bool) {
_approve(msg.sender, spender, _allowances[msg.sender][spender].sub(subtractedValue));
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 {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_balances[sender] = _balances[sender].sub(amount);
_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 {
require(account != address(0), "ERC20: mint to the zero address");
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
/**
* @dev Destoys `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 value) internal {
require(account != address(0), "ERC20: burn from the zero address");
_totalSupply = _totalSupply.sub(value);
_balances[account] = _balances[account].sub(value);
emit Transfer(account, address(0), value);
}
/**
* @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 value) internal {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = value;
emit Approval(owner, spender, value);
}
/**
* @dev Destoys `amount` tokens from `account`.`amount` is then deducted
* from the caller's allowance.
*
* See `_burn` and `_approve`.
*/
function _burnFrom(address account, uint256 amount) internal {
_burn(account, amount);
_approve(account, msg.sender, _allowances[account][msg.sender].sub(amount));
}
}
// File: @openzeppelin/contracts/access/Roles.sol
pragma solidity ^0.5.0;
/**
* @title Roles
* @dev Library for managing addresses assigned to a Role.
*/
library Roles {
struct Role {
mapping (address => bool) bearer;
}
/**
* @dev Give an account access to this role.
*/
function add(Role storage role, address account) internal {
require(!has(role, account), "Roles: account already has role");
role.bearer[account] = true;
}
/**
* @dev Remove an account's access to this role.
*/
function remove(Role storage role, address account) internal {
require(has(role, account), "Roles: account does not have role");
role.bearer[account] = false;
}
/**
* @dev Check if an account has this role.
* @return bool
*/
function has(Role storage role, address account) internal view returns (bool) {
require(account != address(0), "Roles: account is the zero address");
return role.bearer[account];
}
}
// File: @openzeppelin/contracts/access/roles/MinterRole.sol
pragma solidity ^0.5.0;
contract MinterRole {
using Roles for Roles.Role;
event MinterAdded(address indexed account);
event MinterRemoved(address indexed account);
Roles.Role private _minters;
constructor () internal {
_addMinter(msg.sender);
}
modifier onlyMinter() {
require(isMinter(msg.sender), "MinterRole: caller does not have the Minter role");
_;
}
function isMinter(address account) public view returns (bool) {
return _minters.has(account);
}
function addMinter(address account) public onlyMinter {
_addMinter(account);
}
function renounceMinter() public {
_removeMinter(msg.sender);
}
function _addMinter(address account) internal {
_minters.add(account);
emit MinterAdded(account);
}
function _removeMinter(address account) internal {
_minters.remove(account);
emit MinterRemoved(account);
}
}
// File: @openzeppelin/contracts/token/ERC20/ERC20Mintable.sol
pragma solidity ^0.5.0;
/**
* @dev Extension of `ERC20` that adds a set of accounts with the `MinterRole`,
* which have permission to mint (create) new tokens as they see fit.
*
* At construction, the deployer of the contract is the only minter.
*/
contract ERC20Mintable is ERC20, MinterRole {
/**
* @dev See `ERC20._mint`.
*
* Requirements:
*
* - the caller must have the `MinterRole`.
*/
function mint(address account, uint256 amount) public onlyMinter returns (bool) {
_mint(account, amount);
return true;
}
}
// File: @openzeppelin/contracts/token/ERC20/ERC20Detailed.sol
pragma solidity ^0.5.0;
/**
* @dev Optional functions from the ERC20 standard.
*/
contract ERC20Detailed is IERC20 {
string private _name;
string private _symbol;
uint8 private _decimals;
/**
* @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
* these values are immutable: they can only be set once during
* construction.
*/
constructor (string memory name, string memory symbol, uint8 decimals) public {
_name = name;
_symbol = symbol;
_decimals = decimals;
}
/**
* @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.
*
* > Note that 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;
}
}
// File: contracts/CfoCoin.sol
pragma solidity >=0.5.0;
/**
* @title CfoCoin contract
*/
contract CfoCoin is ERC20Mintable, ERC20Detailed {
uint noOfTokens = 10000000000; // 10,000,000,000 (10B)
// Address of cfgcoin vault (a CfoCoinMultiSigWallet contract)
// The vault will have all the cfgcoin issued and the operation
// on its token will be protected by multi signing.
// In addtion, vault can recall(transfer back) the reserved amount
// from some address.
address internal vault;
// Address of cfgcoin owner (a CfoCoinMultiSigWallet contract)
// The owner can change admin and vault address, but the change operation
// will be protected by multi signing.
address internal owner;
// Address of cfgcoin admin (a CfoCoinMultiSigWallet contract)
// The admin can change reserve. The reserve is the amount of token
// assigned to some address but not permitted to use.
// Once the signers of the admin agree with removing the reserve,
// they can change the reserve to zero to permit the user to use all reserved
// amount. So in effect, reservation will postpone the use of some tokens
// being used until all stakeholders agree with giving permission to use that
// token to the token owner.
// All admin operation will be protected by multi signing.
address internal admin;
event OwnerChanged(address indexed previousOwner, address indexed newOwner);
event VaultChanged(address indexed previousVault, address indexed newVault);
event AdminChanged(address indexed previousAdmin, address indexed newAdmin);
event ReserveChanged(address indexed _address, uint amount);
event Recalled(address indexed from, uint amount);
// for debugging
event MsgAndValue(string message, bytes32 value);
/**
* @dev reserved number of tokens per each address
*
* To limit token transaction for some period by the admin or owner,
* each address' balance cannot become lower than this amount
*
*/
mapping(address => uint) public reserves;
/**
* @dev modifier to limit access to the owner only
*/
modifier onlyOwner() {
require(msg.sender == owner);
_;
}
/**
* @dev limit access to the vault only
*/
modifier onlyVault() {
require(msg.sender == vault);
_;
}
/**
* @dev limit access to the admin only
*/
modifier onlyAdmin() {
require(msg.sender == admin);
_;
}
/**
* @dev limit access to admin or vault
*/
modifier onlyAdminOrVault() {
require(msg.sender == vault || msg.sender == admin);
_;
}
/**
* @dev limit access to owner or vault
*/
modifier onlyOwnerOrVault() {
require(msg.sender == owner || msg.sender == vault);
_;
}
/**
* @dev limit access to owner or admin
*/
modifier onlyAdminOrOwner() {
require(msg.sender == owner || msg.sender == admin);
_;
}
/**
* @dev limit access to owner or admin or vault
*/
modifier onlyAdminOrOwnerOrVault() {
require(msg.sender == owner || msg.sender == vault || msg.sender == admin);
_;
}
/**
* @dev initialize QRC20(ERC20)
*
* all token will deposit into the vault
* later, the vault, owner will be multi sign contract to protect privileged operations
*
* @param _symbol token symbol
* @param _name token name
* @param _owner owner address
* @param _admin admin address
* @param _vault vault address
*/
constructor (string memory _symbol, string memory _name, address _owner,
address _admin, address _vault) ERC20Detailed(_name, _symbol, 9)
public {
require(bytes(_symbol).length > 0);
require(bytes(_name).length > 0);
owner = _owner;
admin = _admin;
vault = _vault;
// mint coins to the vault
_mint(vault, noOfTokens * (10 ** uint(decimals())));
}
/**
* @dev change the amount of reserved token
* reserve should be less than or equal to the current token balance
*
* Refer to the comment on the admin if you want to know more.
*
* @param _address the target address whose token will be frozen for future use
* @param _reserve the amount of reserved token
*
*/
function setReserve(address _address, uint _reserve) public onlyAdmin {
require(_reserve <= totalSupply());
require(_address != address(0));
reserves[_address] = _reserve;
emit ReserveChanged(_address, _reserve);
}
/**
* @dev transfer token from sender to other
* the result balance should be greater than or equal to the reserved token amount
*/
function transfer(address _to, uint256 _value) public returns (bool) {
// check the reserve
require(balanceOf(msg.sender) - _value >= reserveOf(msg.sender));
return super.transfer(_to, _value);
}
/**
* @dev change vault address
* BEWARE! this withdraw all token from old vault and store it to the new vault
* and new vault's allowed, reserve will be set to zero
* @param _newVault new vault address
*/
function setVault(address _newVault) public onlyOwner {
require(_newVault != address(0));
require(_newVault != vault);
address _oldVault = vault;
// change vault address
vault = _newVault;
emit VaultChanged(_oldVault, _newVault);
// vault cannot have any allowed or reserved amount!!!
_approve(_newVault, msg.sender, 0);
reserves[_newVault] = 0;
// adjust balance
uint _value = balanceOf(_oldVault);
_transfer(_oldVault, _newVault, _value);
}
/**
* @dev change owner address
* @param _newOwner new owner address
*/
function setOwner(address _newOwner) public onlyVault {
require(_newOwner != address(0));
require(_newOwner != owner);
owner = _newOwner;
emit OwnerChanged(owner, _newOwner);
}
/**
* @dev change admin address
* @param _newAdmin new admin address
*/
function setAdmin(address _newAdmin) public onlyOwnerOrVault {
require(_newAdmin != address(0));
require(_newAdmin != admin);
admin = _newAdmin;
emit AdminChanged(admin, _newAdmin);
}
/**
* @dev transfer a part of reserved amount to the vault
*
* Refer to the comment on the vault if you want to know more.
*
* @param _from the address from which the reserved token will be taken
* @param _amount the amount of token to be taken
*/
function recall(address _from, uint _amount) public onlyAdmin {
require(_from != address(0));
require(_amount > 0);
uint currentReserve = reserveOf(_from);
uint currentBalance = balanceOf(_from);
require(currentReserve >= _amount);
require(currentBalance >= _amount);
uint newReserve = currentReserve - _amount;
reserves[_from] = newReserve;
emit ReserveChanged(_from, newReserve);
// transfer token _from to vault
_transfer(_from, vault, _amount);
emit Recalled(_from, _amount);
}
/**
* @dev Transfer tokens from one address to another
*
* The _from's CFO balance should be larger than the reserved amount(reserves[_from]) plus _value.
*
*/
function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
require(_value <= balanceOf(_from).sub(reserves[_from]));
return super.transferFrom(_from, _to, _value);
}
function getOwner() public view onlyAdminOrOwnerOrVault returns (address) {
return owner;
}
function getVault() public view onlyAdminOrOwnerOrVault returns (address) {
return vault;
}
function getAdmin() public view onlyAdminOrOwnerOrVault returns (address) {
return admin;
}
function getOneCfoCoin() public view returns (uint) {
return (10 ** uint(decimals()));
}
/**
* @dev get the amount of reserved token
*/
function reserveOf(address _address) public view returns (uint _reserve) {
return reserves[_address];
}
/**
* @dev get the amount reserved token of the sender
*/
function reserve() public view returns (uint _reserve) {
return reserves[msg.sender];
}
}
