Cojam

// File: contracts/ERC20/IERC20.sol

pragma solidity ^0.6.0;

/**
 * @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.
     *
     * IMPORTANT: 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);

}

// File: contracts/ERC20/ERC20Detailed.sol

pragma solidity ^0.6.0;


/**
 * @dev Optional functions from the ERC20 standard.
 */
abstract 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: 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/ERC20/GSN/Context.sol

pragma solidity ^0.6.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }

    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: contracts/ERC20/SafeMath.sol

pragma solidity ^0.6.0;

/**
 * @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, "SM:28");

        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) {
        return sub(a, b, "SM:43");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        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, "SM:82");

        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) {
        return div(a, b, "SM:99");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message 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.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        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) {
        return mod(a, b, "SM:144");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message 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.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: contracts/ERC20/ERC20.sol

pragma solidity ^0.6.0;




contract ERC20 is Context {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    function __totalSupply() internal view returns (uint256) {
        return _totalSupply;
    }

    function __balanceOf(address account) internal view returns (uint256) {
        return _balances[account];
    }

    function __transfer(address recipient, uint256 amount) internal returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    function __allowance(address owner, address spender) internal view returns (uint256) {
        return _allowances[owner][spender];
    }

    function __approve(address spender, uint256 amount) internal returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    function __transferFrom(address sender, address recipient, uint256 amount) internal returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20:40"));
        return true;
    }

    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20:44");
        require(recipient != address(0), "ERC20:46");
        _balances[sender] = _balances[sender].sub(amount, "ERC20:50");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20:56");
        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    function _approve(address owner, address spender, uint256 amount) private {
        require(owner != address(0), "ERC20:66");
        require(spender != address(0), "ERC20:67");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: contracts/library/Ownable.sol

pragma solidity ^0.6.0;

contract Ownable {
    address internal _owner;

    event OwnershipTransferred(
        address indexed currentOwner,
        address indexed newOwner
    );

    constructor() internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), msg.sender);
    }

    modifier onlyOwner() {
        require(
            msg.sender == _owner,
            "Ownable : Function called by unauthorized user."
        );
        _;
    }

    function owner() external view returns (address ownerAddress) {
        ownerAddress = _owner;
    }

    function transferOwnership(address newOwner)
        public
        onlyOwner
        returns (bool success)
    {
        require(newOwner != address(0), "Ownable/transferOwnership : cannot transfer ownership to zero address");
        success = _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal returns (bool success) {
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
        success = true;
    }
}

// File: contracts/library/UserManager.sol

pragma solidity ^0.6.0;

contract UserManager {
    struct AddressSet {
        mapping(address => bool) flags;
    }

    AddressSet internal lockedUsers = AddressSet();

    function _insertLockUser(address value)
          internal
          returns (bool)
      {
          if (lockedUsers.flags[value])
              return false; // already there
          lockedUsers.flags[value] = true;
          return true;
      }

      function _removeLockUser(address value)
          internal
          returns (bool)
      {
          if (!lockedUsers.flags[value])
              return false; // not there
          lockedUsers.flags[value] = false;
          return true;
      }

      function _containsLockUser(address value)
          internal
          view
          returns (bool)
      {
          return lockedUsers.flags[value];
      }

    modifier isAllowedUser(address user) {
        require(_containsLockUser(user) == false, "sender is locked user");    // 차단된 사용자가 아니어야 한다!
        _;
    }
}

// File: contracts/CojamToken.sol

pragma solidity ^0.6.0;





contract CojamToken is IERC20, ERC20, ERC20Detailed, Ownable, UserManager {

    event LockUser(address user);
    event UnlockUser(address user);

    constructor() ERC20Detailed("Cojam", "CT", 18) public {
        uint256 initialSupply = 5000000000 * (10 ** 18);

        _owner = msg.sender;
        _mint(msg.sender, initialSupply);
    }

    /**
     * 관리자가 사용자의 차단 여부를 확인하는 함수
     * */
    function isLock(address target) external view returns(bool) {
        return _containsLockUser(target);
    }

    /**
     * 관리자가 사용자를 차단하는 함수
     * */
    function lock(address[] memory targets) public onlyOwner returns(bool[] memory) {
        bool[] memory results = new bool[](targets.length);

        for(uint256 ii=0; ii<targets.length; ii++){
            require(_owner != targets[ii], "can not lock owner");     // 관리자 주소가 컨트롤 되어서는 안 된다!
            results[ii] = _insertLockUser(targets[ii]);
            emit LockUser(targets[ii]);
        }

        return results;
    }

    /**
     * 관리자가 사용자를 차단해제 하는 함수
     * */
    function unlock(address[] memory targets) public onlyOwner returns(bool[] memory) {
        bool[] memory results = new bool[](targets.length);

        for(uint256 ii=0; ii<targets.length; ii++){
            require(_owner != targets[ii], "can not unlock owner");     // 관리자 주소가 컨트롤 되어서는 안 된다!
            results[ii] = _removeLockUser(targets[ii]);
            emit UnlockUser(targets[ii]);
        }

        return results;
    }
    /**
     * ERC20 기본 함수
    **/
    function transfer(address recipient, uint256 amount) external override isAllowedUser(msg.sender) returns (bool){
        return __transfer(recipient, amount);
    }

    function totalSupply() external override view returns (uint256){
        return __totalSupply();
    }

    function balanceOf(address account) external override view returns (uint256){
        return __balanceOf(account);
    }

    function allowance(address owner, address spender) external view override returns (uint256){
        return __allowance(owner, spender);
    }

    function approve(address spender, uint256 amount) external override isAllowedUser(msg.sender) returns (bool){
        return __approve(spender, amount);
    }

    function transferFrom(address sender, address recipient, uint256 amount) external override isAllowedUser(sender) returns (bool){
        return __transferFrom(sender, recipient, amount);
    }
}

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  "metadata": {
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