ERC223_token.sol

// SPDX-License-Identifier: No License (None)
pragma solidity 0.8.19;

library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * This test is non-exhaustive, and there may be false-negatives: during the
     * execution of a contract's constructor, its address will be reported as
     * not containing a contract.
     *
     * > It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies in extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }
}

interface IERC223 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the token decimals.
     */
    function decimals() external view returns (uint8);

    /**
     * @dev Returns the token symbol.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the token name.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the token standard.
     */
    function standard() external pure returns (string memory);

    /**
     * @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);

    function transfer(
        address recipient,
        uint256 amount,
        bytes calldata data
    ) 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);

    /**
     * @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);

    event TransferData(bytes data);

    /**
     * @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
    );
}

interface IERC223Recipient {
    function tokenReceived(
        address _from,
        uint _value,
        bytes calldata _data
    ) external;
}

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), msg.sender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == msg.sender, "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(
            newOwner != address(0),
            "Ownable: new owner is the zero address"
        );
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

contract ERC223 is IERC223, Ownable {
    using Address for address;

    mapping(address => uint256) private _balances;

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

    uint256 private _totalSupply;
    uint8 private _decimals;
    string private _symbol;
    string private _name;
    address public minter;
    event SetMinter(address previousMinter, address newMinter);
    event Rescued(address to, bytes data);

    /**
     * @dev Throws if called by any account other than the minter.
     */
    modifier onlyMinter() {
        require(msg.sender == minter, "Caller is not admin");
        _;
    }

    // set minter to bridge contract to avoid initialize this implementation contract
    constructor() {
        minter = msg.sender; // set bridge as minter
        emit SetMinter(address(0), minter);
        _name = "LiveDiff";
        _symbol = "DIFF";
        _decimals = 18;
    }

    // allow owner to change minter. Set minter to address(0) to forbid minting
    function setMinter(address newMinter) external onlyOwner {
        require(minter != address(0), "Minting is forbidden");
        emit SetMinter(minter, newMinter);
        minter = newMinter;
    }

    /**
     * @dev Mint tokens to user in amount of his deposit. Used by bridge to mint wrapped tokens
     * @param user - address of user's wallet
     * @param amount - amount of token to mint (should be equivalent of USDT amount of deposit)
     */
    function mint(address user, uint256 amount) external onlyMinter {
        _mint(user, amount);
    }

    /**
     * @dev Returns the token decimals.
     */
    function decimals() external view override returns (uint8) {
        return _decimals;
    }

    /**
     * @dev Returns the token symbol.
     */
    function symbol() external view override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the token name.
     */
    function name() external view override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the token standard.
     */
    function standard() external pure override returns (string memory) {
        return "erc223";
    }

    /**
     * @dev See {ERC223-totalSupply}.
     */
    function totalSupply() external view override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {ERC223-balanceOf}.
     */
    function balanceOf(
        address account
    ) external view override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {ERC223-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(
        address recipient,
        uint amount
    ) external override returns (bool) {
        _transfer(msg.sender, recipient, amount);

        if (recipient.isContract()) {
            IERC223Recipient(recipient).tokenReceived(msg.sender, amount, "");
        }
        emit TransferData("");
        return true;
    }

    function transfer(
        address recipient,
        uint amount,
        bytes calldata data
    ) external override returns (bool) {
        _transfer(msg.sender, recipient, amount);
        if (recipient.isContract()) {
            IERC223Recipient(recipient).tokenReceived(msg.sender, amount, data);
        }
        emit TransferData(data);
        return true;
    }

    /**
     * @dev See {ERC223-allowance}.
     */
    function allowance(
        address owner,
        address spender
    ) external view override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {ERC223-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(
        address spender,
        uint256 amount
    ) external override returns (bool) {
        _approve(msg.sender, spender, amount);
        return true;
    }

    /**
     * @dev See {ERC223-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC223};
     *
     * 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
    ) external override returns (bool) {
        _transfer(sender, recipient, amount);
        require(
            _allowances[sender][msg.sender] >= amount,
            "ERC223: transfer amount exceeds allowance"
        );
        _approve(sender, msg.sender, _allowances[sender][msg.sender] - 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 {ERC223-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] + 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 {ERC223-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) {
        uint256 newAllawnce;
        if (_allowances[spender][msg.sender] > subtractedValue) {
            newAllawnce = _allowances[msg.sender][spender] - subtractedValue;
        }
        _approve(msg.sender, spender, newAllawnce);
        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), "ERC223: transfer from the zero address");
        require(
            recipient != address(0),
            "ERC223: transfer to the zero address"
        );
        require(
            _balances[sender] >= amount,
            "ERC223: transfer amount exceeds balance"
        );
        _balances[sender] = _balances[sender] - amount;
        _balances[recipient] = _balances[recipient] + 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), "ERC223: mint to the zero address");

        _totalSupply = _totalSupply + amount;
        _balances[account] = _balances[account] + 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 {
        require(account != address(0), "ERC223: burn from the zero address");
        require(
            _balances[account] >= amount,
            "ERC223: burn amount exceeds balance"
        );
        _balances[account] = _balances[account] - amount;
        _totalSupply = _totalSupply - 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 {
        require(owner != address(0), "ERC223: approve from the zero address");
        require(spender != address(0), "ERC223: approve to the zero address");

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

    /**
     * @dev Destroys `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);
        require(
            _allowances[account][msg.sender] >= amount,
            "ERC223: transfer amount exceeds allowance"
        );
        _approve(
            account,
            msg.sender,
            _allowances[account][msg.sender] - amount
        );
    }

    function burnFrom(address account, uint256 amount) external returns (bool) {
        _burnFrom(account, amount);
        return true;
    }

    function burn(uint256 amount) external returns (bool) {
        _burn(msg.sender, amount);
        return true;
    }

    event Rescue(address _token, uint256 _amount);

    function rescueTokens(address _token) external onlyOwner {
        uint256 amount = IERC223(_token).balanceOf(address(this));
        safeTransfer(_token, msg.sender, amount);
        emit Rescue(_token, amount);
    }

    function safeTransfer(address token, address to, uint value) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(
            abi.encodeWithSelector(0xa9059cbb, to, value)
        );
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            "TransferHelper: TRANSFER_FAILED"
        );
    }
}