Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity 0.8.6;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/draft-ERC20Permit.sol";
import "@paulrberg/contracts/token/erc20/Erc20Permit.sol";
import "./interfaces/ITickets.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
contract Tickets is ERC20, ERC20Permit, Ownable, ITickets {
constructor(string memory _name, string memory _symbol)
ERC20(_name, _symbol)
ERC20Permit(_name)
{}
function print(address _account, uint256 _amount)
external
override
onlyOwner
{
return _mint(_account, _amount);
}
function redeem(address _account, uint256 _amount)
external
override
onlyOwner
{
return _burn(_account, _amount);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";
/**
* @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 {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* 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 Context, IERC20, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
/**
* @dev Sets the values for {name} and {symbol}.
*
* The default value of {decimals} is 18. To select a different value for
* {decimals} you should overload it.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override 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 this function is
* overridden;
*
* 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 virtual override returns (uint8) {
return 18;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual 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);
uint256 currentAllowance = _allowances[sender][_msgSender()];
require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
unchecked {
_approve(sender, _msgSender(), currentAllowance - 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 virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][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 {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) {
uint256 currentAllowance = _allowances[_msgSender()][spender];
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(_msgSender(), spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `sender` to `recipient`.
*
* This 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);
uint256 senderBalance = _balances[sender];
require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[sender] = senderBalance - amount;
}
_balances[recipient] += amount;
emit Transfer(sender, recipient, amount);
_afterTokenTransfer(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:
*
* - `account` 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 += amount;
_balances[account] += amount;
emit Transfer(address(0), account, amount);
_afterTokenTransfer(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);
uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
}
_totalSupply -= amount;
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This 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 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 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 {}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been 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 _afterTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./draft-IERC20Permit.sol";
import "../ERC20.sol";
import "../../../utils/cryptography/draft-EIP712.sol";
import "../../../utils/cryptography/ECDSA.sol";
import "../../../utils/Counters.sol";
/**
* @dev Implementation of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
* https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
*
* Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
* presenting a message signed by the account. By not relying on `{IERC20-approve}`, the token holder account doesn't
* need to send a transaction, and thus is not required to hold Ether at all.
*
* _Available since v3.4._
*/
abstract contract ERC20Permit is ERC20, IERC20Permit, EIP712 {
using Counters for Counters.Counter;
mapping(address => Counters.Counter) private _nonces;
// solhint-disable-next-line var-name-mixedcase
bytes32 private immutable _PERMIT_TYPEHASH =
keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
/**
* @dev Initializes the {EIP712} domain separator using the `name` parameter, and setting `version` to `"1"`.
*
* It's a good idea to use the same `name` that is defined as the ERC20 token name.
*/
constructor(string memory name) EIP712(name, "1") {}
/**
* @dev See {IERC20Permit-permit}.
*/
function permit(
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) public virtual override {
require(block.timestamp <= deadline, "ERC20Permit: expired deadline");
bytes32 structHash = keccak256(abi.encode(_PERMIT_TYPEHASH, owner, spender, value, _useNonce(owner), deadline));
bytes32 hash = _hashTypedDataV4(structHash);
address signer = ECDSA.recover(hash, v, r, s);
require(signer == owner, "ERC20Permit: invalid signature");
_approve(owner, spender, value);
}
/**
* @dev See {IERC20Permit-nonces}.
*/
function nonces(address owner) public view virtual override returns (uint256) {
return _nonces[owner].current();
}
/**
* @dev See {IERC20Permit-DOMAIN_SEPARATOR}.
*/
// solhint-disable-next-line func-name-mixedcase
function DOMAIN_SEPARATOR() external view override returns (bytes32) {
return _domainSeparatorV4();
}
/**
* @dev "Consume a nonce": return the current value and increment.
*
* _Available since v4.1._
*/
function _useNonce(address owner) internal virtual returns (uint256 current) {
Counters.Counter storage nonce = _nonces[owner];
current = nonce.current();
nonce.increment();
}
}
// SPDX-License-Identifier: WTFPL
// solhint-disable var-name-mixedcase
pragma solidity >=0.8.4;
import "./Erc20.sol";
import "./IErc20Permit.sol";
/// @notice Emitted when the recovered owner does not match the actual owner.
error Erc20Permit__InvalidSignature(uint8 v, bytes32 r, bytes32 s);
/// @notice Emitted when the owner is the zero address.
error Erc20Permit__OwnerZeroAddress();
/// @notice Emitted when the permit expired.
error Erc20Permit__PermitExpired(uint256 deadline);
/// @notice Emitted when the recovered owner is the zero address.
error Erc20Permit__RecoveredOwnerZeroAddress();
/// @notice Emitted when the spender is the zero address.
error Erc20Permit__SpenderZeroAddress();
/// @title Erc20Permit
/// @author Paul Razvan Berg
contract Erc20Permit is
IErc20Permit, // one dependency
Erc20 // one dependency
{
/// PUBLIC STORAGE ///
/// @inheritdoc IErc20Permit
bytes32 public immutable override DOMAIN_SEPARATOR;
/// @inheritdoc IErc20Permit
bytes32 public constant override PERMIT_TYPEHASH =
0xfc77c2b9d30fe91687fd39abb7d16fcdfe1472d065740051ab8b13e4bf4a617f;
/// @inheritdoc IErc20Permit
mapping(address => uint256) public override nonces;
/// @inheritdoc IErc20Permit
string public constant override version = "1";
/// CONSTRUCTOR ///
constructor(
string memory _name,
string memory _symbol,
uint8 _decimals
) Erc20(_name, _symbol, _decimals) {
uint256 chainId;
// solhint-disable-next-line no-inline-assembly
assembly {
chainId := chainid()
}
DOMAIN_SEPARATOR = keccak256(
abi.encode(
keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
keccak256(bytes(name)),
keccak256(bytes(version)),
chainId,
address(this)
)
);
}
/// PUBLIC NON-CONSTANT FUNCTIONS ///
/// @inheritdoc IErc20Permit
function permit(
address owner,
address spender,
uint256 amount,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) external override {
if (owner == address(0)) {
revert Erc20Permit__OwnerZeroAddress();
}
if (spender == address(0)) {
revert Erc20Permit__SpenderZeroAddress();
}
if (deadline < block.timestamp) {
revert Erc20Permit__PermitExpired(deadline);
}
// It's safe to use the "+" operator here because the nonce cannot realistically overflow, ever.
bytes32 hashStruct = keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, amount, nonces[owner]++, deadline));
bytes32 digest = keccak256(abi.encodePacked("\x19\x01", DOMAIN_SEPARATOR, hashStruct));
address recoveredOwner = ecrecover(digest, v, r, s);
if (recoveredOwner == address(0)) {
revert Erc20Permit__RecoveredOwnerZeroAddress();
}
if (recoveredOwner != owner) {
revert Erc20Permit__InvalidSignature(v, r, s);
}
approveInternal(owner, spender, amount);
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.6;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
interface ITickets is IERC20 {
function print(address _account, uint256 _amount) external;
function redeem(address _account, uint256 _amount) external;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
* @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 is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() {
_setOwner(_msgSender());
}
/**
* @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() == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
_setOwner(address(0));
}
/**
* @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");
_setOwner(newOwner);
}
function _setOwner(address newOwner) private {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
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);
/**
* @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);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/
interface IERC20Metadata is IERC20 {
/**
* @dev Returns the name of the token.
*/
function name() external view returns (string memory);
/**
* @dev Returns the symbol of the token.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the decimals places of the token.
*/
function decimals() external view returns (uint8);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/*
* @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 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.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
* https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
*
* Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
* presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
* need to send a transaction, and thus is not required to hold Ether at all.
*/
interface IERC20Permit {
/**
* @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
* given ``owner``'s signed approval.
*
* IMPORTANT: The same issues {IERC20-approve} has related to transaction
* ordering also apply here.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `deadline` must be a timestamp in the future.
* - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
* over the EIP712-formatted function arguments.
* - the signature must use ``owner``'s current nonce (see {nonces}).
*
* For more information on the signature format, see the
* https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
* section].
*/
function permit(
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) external;
/**
* @dev Returns the current nonce for `owner`. This value must be
* included whenever a signature is generated for {permit}.
*
* Every successful call to {permit} increases ``owner``'s nonce by one. This
* prevents a signature from being used multiple times.
*/
function nonces(address owner) external view returns (uint256);
/**
* @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
*/
// solhint-disable-next-line func-name-mixedcase
function DOMAIN_SEPARATOR() external view returns (bytes32);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./ECDSA.sol";
/**
* @dev https://eips.ethereum.org/EIPS/eip-712[EIP 712] is a standard for hashing and signing of typed structured data.
*
* The encoding specified in the EIP is very generic, and such a generic implementation in Solidity is not feasible,
* thus this contract does not implement the encoding itself. Protocols need to implement the type-specific encoding
* they need in their contracts using a combination of `abi.encode` and `keccak256`.
*
* This contract implements the EIP 712 domain separator ({_domainSeparatorV4}) that is used as part of the encoding
* scheme, and the final step of the encoding to obtain the message digest that is then signed via ECDSA
* ({_hashTypedDataV4}).
*
* The implementation of the domain separator was designed to be as efficient as possible while still properly updating
* the chain id to protect against replay attacks on an eventual fork of the chain.
*
* NOTE: This contract implements the version of the encoding known as "v4", as implemented by the JSON RPC method
* https://docs.metamask.io/guide/signing-data.html[`eth_signTypedDataV4` in MetaMask].
*
* _Available since v3.4._
*/
abstract contract EIP712 {
/* solhint-disable var-name-mixedcase */
// Cache the domain separator as an immutable value, but also store the chain id that it corresponds to, in order to
// invalidate the cached domain separator if the chain id changes.
bytes32 private immutable _CACHED_DOMAIN_SEPARATOR;
uint256 private immutable _CACHED_CHAIN_ID;
bytes32 private immutable _HASHED_NAME;
bytes32 private immutable _HASHED_VERSION;
bytes32 private immutable _TYPE_HASH;
/* solhint-enable var-name-mixedcase */
/**
* @dev Initializes the domain separator and parameter caches.
*
* The meaning of `name` and `version` is specified in
* https://eips.ethereum.org/EIPS/eip-712#definition-of-domainseparator[EIP 712]:
*
* - `name`: the user readable name of the signing domain, i.e. the name of the DApp or the protocol.
* - `version`: the current major version of the signing domain.
*
* NOTE: These parameters cannot be changed except through a xref:learn::upgrading-smart-contracts.adoc[smart
* contract upgrade].
*/
constructor(string memory name, string memory version) {
bytes32 hashedName = keccak256(bytes(name));
bytes32 hashedVersion = keccak256(bytes(version));
bytes32 typeHash = keccak256(
"EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
);
_HASHED_NAME = hashedName;
_HASHED_VERSION = hashedVersion;
_CACHED_CHAIN_ID = block.chainid;
_CACHED_DOMAIN_SEPARATOR = _buildDomainSeparator(typeHash, hashedName, hashedVersion);
_TYPE_HASH = typeHash;
}
/**
* @dev Returns the domain separator for the current chain.
*/
function _domainSeparatorV4() internal view returns (bytes32) {
if (block.chainid == _CACHED_CHAIN_ID) {
return _CACHED_DOMAIN_SEPARATOR;
} else {
return _buildDomainSeparator(_TYPE_HASH, _HASHED_NAME, _HASHED_VERSION);
}
}
function _buildDomainSeparator(
bytes32 typeHash,
bytes32 nameHash,
bytes32 versionHash
) private view returns (bytes32) {
return keccak256(abi.encode(typeHash, nameHash, versionHash, block.chainid, address(this)));
}
/**
* @dev Given an already https://eips.ethereum.org/EIPS/eip-712#definition-of-hashstruct[hashed struct], this
* function returns the hash of the fully encoded EIP712 message for this domain.
*
* This hash can be used together with {ECDSA-recover} to obtain the signer of a message. For example:
*
* ```solidity
* bytes32 digest = _hashTypedDataV4(keccak256(abi.encode(
* keccak256("Mail(address to,string contents)"),
* mailTo,
* keccak256(bytes(mailContents))
* )));
* address signer = ECDSA.recover(digest, signature);
* ```
*/
function _hashTypedDataV4(bytes32 structHash) internal view virtual returns (bytes32) {
return ECDSA.toTypedDataHash(_domainSeparatorV4(), structHash);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
*
* These functions can be used to verify that a message was signed by the holder
* of the private keys of a given address.
*/
library ECDSA {
/**
* @dev Returns the address that signed a hashed message (`hash`) with
* `signature`. This address can then be used for verification purposes.
*
* The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
* this function rejects them by requiring the `s` value to be in the lower
* half order, and the `v` value to be either 27 or 28.
*
* IMPORTANT: `hash` _must_ be the result of a hash operation for the
* verification to be secure: it is possible to craft signatures that
* recover to arbitrary addresses for non-hashed data. A safe way to ensure
* this is by receiving a hash of the original message (which may otherwise
* be too long), and then calling {toEthSignedMessageHash} on it.
*
* Documentation for signature generation:
* - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
* - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
*/
function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
// Check the signature length
// - case 65: r,s,v signature (standard)
// - case 64: r,vs signature (cf https://eips.ethereum.org/EIPS/eip-2098) _Available since v4.1._
if (signature.length == 65) {
bytes32 r;
bytes32 s;
uint8 v;
// ecrecover takes the signature parameters, and the only way to get them
// currently is to use assembly.
assembly {
r := mload(add(signature, 0x20))
s := mload(add(signature, 0x40))
v := byte(0, mload(add(signature, 0x60)))
}
return recover(hash, v, r, s);
} else if (signature.length == 64) {
bytes32 r;
bytes32 vs;
// ecrecover takes the signature parameters, and the only way to get them
// currently is to use assembly.
assembly {
r := mload(add(signature, 0x20))
vs := mload(add(signature, 0x40))
}
return recover(hash, r, vs);
} else {
revert("ECDSA: invalid signature length");
}
}
/**
* @dev Overload of {ECDSA-recover} that receives the `r` and `vs` short-signature fields separately.
*
* See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
*
* _Available since v4.2._
*/
function recover(
bytes32 hash,
bytes32 r,
bytes32 vs
) internal pure returns (address) {
bytes32 s;
uint8 v;
assembly {
s := and(vs, 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff)
v := add(shr(255, vs), 27)
}
return recover(hash, v, r, s);
}
/**
* @dev Overload of {ECDSA-recover} that receives the `v`, `r` and `s` signature fields separately.
*/
function recover(
bytes32 hash,
uint8 v,
bytes32 r,
bytes32 s
) internal pure returns (address) {
// EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
// unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
// the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
// signatures from current libraries generate a unique signature with an s-value in the lower half order.
//
// If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
// with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
// vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
// these malleable signatures as well.
require(
uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0,
"ECDSA: invalid signature 's' value"
);
require(v == 27 || v == 28, "ECDSA: invalid signature 'v' value");
// If the signature is valid (and not malleable), return the signer address
address signer = ecrecover(hash, v, r, s);
require(signer != address(0), "ECDSA: invalid signature");
return signer;
}
/**
* @dev Returns an Ethereum Signed Message, created from a `hash`. This
* produces hash corresponding to the one signed with the
* https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
* JSON-RPC method as part of EIP-191.
*
* See {recover}.
*/
function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
// 32 is the length in bytes of hash,
// enforced by the type signature above
return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
}
/**
* @dev Returns an Ethereum Signed Typed Data, created from a
* `domainSeparator` and a `structHash`. This produces hash corresponding
* to the one signed with the
* https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
* JSON-RPC method as part of EIP-712.
*
* See {recover}.
*/
function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
return keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @title Counters
* @author Matt Condon (@shrugs)
* @dev Provides counters that can only be incremented, decremented or reset. This can be used e.g. to track the number
* of elements in a mapping, issuing ERC721 ids, or counting request ids.
*
* Include with `using Counters for Counters.Counter;`
*/
library Counters {
struct Counter {
// This variable should never be directly accessed by users of the library: interactions must be restricted to
// the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
// this feature: see https://github.com/ethereum/solidity/issues/4637
uint256 _value; // default: 0
}
function current(Counter storage counter) internal view returns (uint256) {
return counter._value;
}
function increment(Counter storage counter) internal {
unchecked {
counter._value += 1;
}
}
function decrement(Counter storage counter) internal {
uint256 value = counter._value;
require(value > 0, "Counter: decrement overflow");
unchecked {
counter._value = value - 1;
}
}
function reset(Counter storage counter) internal {
counter._value = 0;
}
}
// SPDX-License-Identifier: WTFPL
pragma solidity >=0.8.4;
import "./IErc20.sol";
/// @notice Emitted when the owner is the zero address.
error Erc20__ApproveOwnerZeroAddress();
/// @notice Emitted when the spender is the zero address.
error Erc20__ApproveSpenderZeroAddress();
/// @notice Emitted when burning more tokens than are in the account.
error Erc20__BurnUnderflow(uint256 accountBalance, uint256 burnAmount);
/// @notice Emitted when the holder is the zero address.
error Erc20__BurnZeroAddress();
/// @notice Emitted when the sender did not give the caller a sufficient allowance.
error Erc20__InsufficientAllowance(uint256 allowance, uint256 amount);
/// @notice Emitted when the beneficiary is the zero address.
error Erc20__MintZeroAddress();
/// @notice Emitted when tranferring more tokens than there are in the account.
error Erc20__TransferUnderflow(uint256 senderBalance, uint256 amount);
/// @notice Emitted when the sender is the zero address.
error Erc20__TransferSenderZeroAddress();
/// @notice Emitted when the recipient is the zero address.
error Erc20__TransferRecipientZeroAddress();
/// @title Erc20
/// @author Paul Razvan Berg
contract Erc20 is IErc20 {
/// PUBLIC STORAGE ///
/// @inheritdoc IErc20
string public override name;
/// @inheritdoc IErc20
string public override symbol;
/// @inheritdoc IErc20
uint8 public immutable override decimals;
/// @inheritdoc IErc20
uint256 public override totalSupply;
/// @inheritdoc IErc20
mapping(address => uint256) public override balanceOf;
/// @inheritdoc IErc20
mapping(address => mapping(address => uint256)) public override allowance;
/// CONSTRUCTOR ///
/// @notice All three of these values are immutable: they can only be set once during construction.
/// @param _name Erc20 name of this token.
/// @param _symbol Erc20 symbol of this token.
/// @param _decimals Erc20 decimal precision of this token.
constructor(
string memory _name,
string memory _symbol,
uint8 _decimals
) {
name = _name;
symbol = _symbol;
decimals = _decimals;
}
/// PUBLIC NON-CONSTANT FUNCTIONS ///
/// @inheritdoc IErc20
function approve(address spender, uint256 amount) external virtual override returns (bool) {
approveInternal(msg.sender, spender, amount);
return true;
}
/// @inheritdoc IErc20
function decreaseAllowance(address spender, uint256 subtractedValue) external virtual override returns (bool) {
uint256 newAllowance = allowance[msg.sender][spender] - subtractedValue;
approveInternal(msg.sender, spender, newAllowance);
return true;
}
/// @inheritdoc IErc20
function increaseAllowance(address spender, uint256 addedValue) external virtual override returns (bool) {
uint256 newAllowance = allowance[msg.sender][spender] + addedValue;
approveInternal(msg.sender, spender, newAllowance);
return true;
}
/// @inheritdoc IErc20
function transfer(address recipient, uint256 amount) external virtual override returns (bool) {
transferInternal(msg.sender, recipient, amount);
return true;
}
/// @inheritdoc IErc20
function transferFrom(
address sender,
address recipient,
uint256 amount
) external virtual override returns (bool) {
transferInternal(sender, recipient, amount);
uint256 currentAllowance = allowance[sender][msg.sender];
if (currentAllowance < amount) {
revert Erc20__InsufficientAllowance(currentAllowance, amount);
}
approveInternal(sender, msg.sender, currentAllowance);
return true;
}
/// INTERNAL NON-CONSTANT FUNCTIONS ///
/// @notice Sets `amount` as the allowance of `spender` over the `owner`s tokens.
///
/// @dev Emits an {Approval} event.
///
/// This is internal function is equivalent to `approve`, and can be used to e.g. set automatic
/// allowances for certain subsystems, etc.
///
/// Requirements:
///
/// - `owner` cannot be the zero address.
/// - `spender` cannot be the zero address.
function approveInternal(
address owner,
address spender,
uint256 amount
) internal virtual {
if (owner == address(0)) {
revert Erc20__ApproveOwnerZeroAddress();
}
if (spender == address(0)) {
revert Erc20__ApproveSpenderZeroAddress();
}
allowance[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/// @notice Destroys `burnAmount` tokens from `holder`, reducing the token supply.
///
/// @dev Emits a {Transfer} event.
///
/// Requirements:
///
/// - `holder` must have at least `amount` tokens.
function burnInternal(address holder, uint256 burnAmount) internal {
if (holder == address(0)) {
revert Erc20__BurnZeroAddress();
}
uint256 accountBalance = balanceOf[holder];
if (accountBalance < burnAmount) {
revert Erc20__BurnUnderflow(accountBalance, burnAmount);
}
// Burn the tokens.
unchecked {
balanceOf[holder] = accountBalance - burnAmount;
}
// Reduce the total supply.
totalSupply -= burnAmount;
emit Transfer(holder, address(0), burnAmount);
}
/// @notice Prints new tokens into existence and assigns them to `beneficiary`, increasing the
/// total supply.
///
/// @dev Emits a {Transfer} event.
///
/// Requirements:
///
/// - The beneficiary's balance and the total supply cannot overflow.
function mintInternal(address beneficiary, uint256 mintAmount) internal {
if (beneficiary == address(0)) {
revert Erc20__MintZeroAddress();
}
/// Mint the new tokens.
balanceOf[beneficiary] += mintAmount;
/// Increase the total supply.
totalSupply += mintAmount;
emit Transfer(address(0), beneficiary, mintAmount);
}
/// @notice Moves `amount` tokens from `sender` to `recipient`.
///
/// @dev 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 transferInternal(
address sender,
address recipient,
uint256 amount
) internal virtual {
if (sender == address(0)) {
revert Erc20__TransferSenderZeroAddress();
}
if (recipient == address(0)) {
revert Erc20__TransferRecipientZeroAddress();
}
uint256 senderBalance = balanceOf[sender];
if (senderBalance < amount) {
revert Erc20__TransferUnderflow(senderBalance, amount);
}
unchecked {
balanceOf[sender] = senderBalance - amount;
}
balanceOf[recipient] += amount;
emit Transfer(sender, recipient, amount);
}
}
// SPDX-License-Identifier: WTFPL
// solhint-disable func-name-mixedcase
pragma solidity >=0.8.4;
import "./IErc20.sol";
/// @title IErc20Permit
/// @author Paul Razvan Berg
/// @notice Extension of Erc20 that allows token holders to use their tokens without sending any
/// transactions by setting the allowance with a signature using the `permit` method, and then spend
/// them via `transferFrom`.
/// @dev See https://eips.ethereum.org/EIPS/eip-2612.
interface IErc20Permit is IErc20 {
/// NON-CONSTANT FUNCTIONS ///
/// @notice Sets `amount` as the allowance of `spender` over `owner`'s tokens, assuming the latter's
/// signed approval.
///
/// @dev Emits an {Approval} event.
///
/// IMPORTANT: The same issues Erc20 `approve` has related to transaction
/// ordering also apply here.
///
/// Requirements:
///
/// - `owner` cannot be the zero address.
/// - `spender` cannot be the zero address.
/// - `deadline` must be a timestamp in the future.
/// - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner` over the Eip712-formatted
/// function arguments.
/// - The signature must use `owner`'s current nonce.
function permit(
address owner,
address spender,
uint256 amount,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) external;
/// CONSTANT FUNCTIONS ///
/// @notice The Eip712 domain's keccak256 hash.
function DOMAIN_SEPARATOR() external view returns (bytes32);
/// @notice Provides replay protection.
function nonces(address account) external view returns (uint256);
/// @notice keccak256("Permit(address owner,address spender,uint256 amount,uint256 nonce,uint256 deadline)");
function PERMIT_TYPEHASH() external view returns (bytes32);
/// @notice Eip712 version of this implementation.
function version() external view returns (string memory);
}
// SPDX-License-Identifier: WTFPL
pragma solidity >=0.8.4;
/// @title IErc20
/// @author Paul Razvan Berg
/// @notice Implementation for the Erc20 standard.
///
/// 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 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 Erc 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.
///
/// @dev Forked from OpenZeppelin
/// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.4.0/contracts/token/ERC20/ERC20.sol
interface IErc20 {
/// EVENTS ///
/// @notice Emitted when an approval happens.
/// @param owner The address of the owner of the tokens.
/// @param spender The address of the spender.
/// @param amount The maximum amount that can be spent.
event Approval(address indexed owner, address indexed spender, uint256 amount);
/// @notice Emitted when a transfer happens.
/// @param from The account sending the tokens.
/// @param to The account receiving the tokens.
/// @param amount The amount of tokens transferred.
event Transfer(address indexed from, address indexed to, uint256 amount);
/// CONSTANT FUNCTIONS ///
/// @notice Returns the remaining number of tokens that `spender` will be allowed to spend
/// on behalf of `owner` through {transferFrom}. This is zero by default.
///
/// @dev This value changes when {approve} or {transferFrom} are called.
function allowance(address owner, address spender) external view returns (uint256);
/// @notice Returns the amount of tokens owned by `account`.
function balanceOf(address account) external view returns (uint256);
/// @notice Returns the number of decimals used to get its user representation.
function decimals() external view returns (uint8);
/// @notice Returns the name of the token.
function name() external view returns (string memory);
/// @notice Returns the symbol of the token, usually a shorter version of the name.
function symbol() external view returns (string memory);
/// @notice Returns the amount of tokens in existence.
function totalSupply() external view returns (uint256);
/// NON-CONSTANT FUNCTIONS ///
/// @notice Sets `amount` as the allowance of `spender` over the caller's tokens.
///
/// @dev Emits an {Approval} event.
///
/// 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
///
/// Requirements:
///
/// - `spender` cannot be the zero address.
///
/// @return a boolean value indicating whether the operation succeeded.
function approve(address spender, uint256 amount) external returns (bool);
/// @notice Atomically decreases the allowance granted to `spender` by the caller.
///
/// @dev Emits an {Approval} event indicating the updated allowance.
///
/// This is an alternative to {approve} that can be used as a mitigation for problems described
/// in {Erc20Interface-approve}.
///
/// Requirements:
///
/// - `spender` cannot be the zero address.
/// - `spender` must have allowance for the caller of at least `subtractedValue`.
function decreaseAllowance(address spender, uint256 subtractedValue) external returns (bool);
/// @notice Atomically increases the allowance granted to `spender` by the caller.
///
/// @dev Emits an {Approval} event indicating the updated allowance.
///
/// This is an alternative to {approve} that can be used as a mitigation for the problems described above.
///
/// Requirements:
///
/// - `spender` cannot be the zero address.
function increaseAllowance(address spender, uint256 addedValue) external returns (bool);
/// @notice Moves `amount` tokens from the caller's account to `recipient`.
///
/// @dev Emits a {Transfer} event.
///
/// Requirements:
///
/// - `recipient` cannot be the zero address.
/// - The caller must have a balance of at least `amount`.
///
/// @return a boolean value indicating whether the operation succeeded.
function transfer(address recipient, uint256 amount) external returns (bool);
/// @notice Moves `amount` tokens from `sender` to `recipient` using the allowance mechanism. `amount`
/// `is then deducted from the caller's allowance.
///
/// @dev Emits a {Transfer} event and an {Approval} event indicating the updated allowance. This is
/// not required by the Erc. 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 approed `sender` to spent at least `amount` tokens.
///
/// @return a boolean value indicating whether the operation succeeded.
function transferFrom(
address sender,
address recipient,
uint256 amount
) external returns (bool);
}