@ohgeez/fsushi
Version:
fSUSHI is a protocol built on top of [FlashStake](http://flashstake.io/) and [SushiSwap](https://sushi.com) that enables stakers to get instant, upfront yield without waiting for it to accrue.
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JSON
{
"language": "Solidity",
"sources": {
"contracts/FSushi.sol": {
"content": "// SPDX-License-Identifier: BUSL-1.1\n\npragma solidity ^0.8.17;\n\nimport \"@openzeppelin/contracts/access/Ownable.sol\";\nimport \"@openzeppelin/contracts/token/ERC20/ERC20.sol\";\nimport \"@openzeppelin/contracts/utils/cryptography/ECDSA.sol\";\nimport \"./interfaces/IFSushi.sol\";\nimport \"./libraries/DateUtils.sol\";\n\ncontract FSushi is Ownable, ERC20, IFSushi {\n using DateUtils for uint256;\n\n bytes32 private constant _PERMIT_TYPEHASH =\n keccak256(\"Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)\");\n bytes32 private immutable _CACHED_DOMAIN_SEPARATOR;\n uint256 private immutable _CACHED_CHAIN_ID;\n address private immutable _CACHED_THIS;\n\n bytes32 private immutable _HASHED_NAME;\n bytes32 private immutable _HASHED_VERSION;\n bytes32 private immutable _TYPE_HASH;\n\n uint256 public immutable override startWeek;\n\n mapping(address => bool) public override isMinter;\n bool public override mintersLocked;\n\n mapping(address => uint256) public override nonces;\n /**\n * @return minimum number of minted total supply during the whole week (only available >= startWeek)\n */\n mapping(uint256 => uint256) public override totalSupplyDuring;\n /**\n * @notice totalSupplyDuring is guaranteed to be correct before this week (exclusive)\n */\n uint256 public override lastCheckpoint;\n\n modifier onlyMinter() {\n if (!isMinter[msg.sender]) revert Forbidden();\n _;\n }\n\n constructor() ERC20(\"Flash Sushi Token\", \"fSUSHI\") {\n uint256 nextWeek = block.timestamp.toWeekNumber() + 1;\n startWeek = nextWeek;\n lastCheckpoint = nextWeek;\n\n bytes32 hashedName = keccak256(bytes(\"Flash Sushi Token\"));\n bytes32 hashedVersion = keccak256(bytes(\"1\"));\n bytes32 typeHash = keccak256(\n \"EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)\"\n );\n _HASHED_NAME = hashedName;\n _HASHED_VERSION = hashedVersion;\n _CACHED_CHAIN_ID = block.chainid;\n _CACHED_DOMAIN_SEPARATOR = _buildDomainSeparator(typeHash, hashedName, hashedVersion);\n _CACHED_THIS = address(this);\n _TYPE_HASH = typeHash;\n }\n\n function DOMAIN_SEPARATOR() external view override returns (bytes32) {\n return _domainSeparatorV4();\n }\n\n function _domainSeparatorV4() internal view returns (bytes32) {\n if (address(this) == _CACHED_THIS && block.chainid == _CACHED_CHAIN_ID) {\n return _CACHED_DOMAIN_SEPARATOR;\n } else {\n return _buildDomainSeparator(_TYPE_HASH, _HASHED_NAME, _HASHED_VERSION);\n }\n }\n\n function _buildDomainSeparator(\n bytes32 typeHash,\n bytes32 nameHash,\n bytes32 versionHash\n ) private view returns (bytes32) {\n return keccak256(abi.encode(typeHash, nameHash, versionHash, block.chainid, address(this)));\n }\n\n function _hashTypedDataV4(bytes32 structHash) internal view virtual returns (bytes32) {\n return ECDSA.toTypedDataHash(_domainSeparatorV4(), structHash);\n }\n\n function setMinter(address account, bool _isMinter) external override onlyOwner {\n if (mintersLocked) revert MintersLocked();\n\n isMinter[account] = _isMinter;\n\n emit SetMinter(account, _isMinter);\n }\n\n function lockMinters() external onlyOwner {\n mintersLocked = true;\n\n emit LockMinters();\n }\n\n function permit(\n address owner,\n address spender,\n uint256 value,\n uint256 deadline,\n uint8 v,\n bytes32 r,\n bytes32 s\n ) external override {\n if (block.timestamp > deadline) revert Expired();\n\n bytes32 structHash = keccak256(abi.encode(_PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline));\n\n bytes32 hash = _hashTypedDataV4(structHash);\n\n address signer = ECDSA.recover(hash, v, r, s);\n if (signer != owner) revert InvalidSignature();\n\n _approve(owner, spender, value);\n }\n\n function mint(address to, uint256 amount) external onlyMinter {\n _mint(to, amount);\n\n checkpoint();\n }\n\n function checkpointedTotalSupplyDuring(uint256 week) external override returns (uint256) {\n checkpoint();\n return totalSupplyDuring[week];\n }\n\n /**\n * @dev if this function doesn't get called for 512 weeks (around 9.8 years) this contract breaks\n */\n function checkpoint() public {\n uint256 from = lastCheckpoint;\n uint256 until = block.timestamp.toWeekNumber();\n if (until < from) return;\n\n for (uint256 i; i < 512; ) {\n uint256 week = from + i;\n uint256 old = totalSupplyDuring[week];\n if (week == until) {\n uint256 current = totalSupply();\n if (current > old) {\n totalSupplyDuring[week] = current;\n }\n break;\n } else if (startWeek < week && old == 0) {\n totalSupplyDuring[week] = totalSupplyDuring[week - 1];\n }\n\n unchecked {\n ++i;\n }\n }\n\n lastCheckpoint = until;\n\n emit Checkpoint(until);\n }\n}\n"
},
"contracts/interfaces/IFSushi.sol": {
"content": "// SPDX-License-Identifier: BUSL-1.1\n\npragma solidity ^0.8.0;\n\nimport \"@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol\";\n\ninterface IFSushi is IERC20Metadata {\n error Forbidden();\n error Expired();\n error MintersLocked();\n error InvalidSignature();\n\n event SetMinter(address indexed account, bool indexed isMinter);\n event LockMinters();\n event Checkpoint(uint256 lastCheckpoint);\n\n function DOMAIN_SEPARATOR() external view returns (bytes32);\n\n function startWeek() external view returns (uint256);\n\n function isMinter(address account) external view returns (bool);\n\n function mintersLocked() external view returns (bool);\n\n function nonces(address account) external view returns (uint256);\n\n function totalSupplyDuring(uint256 time) external view returns (uint256);\n\n function lastCheckpoint() external view returns (uint256);\n\n function setMinter(address account, bool _isMinter) external;\n\n function lockMinters() external;\n\n function permit(\n address owner,\n address spender,\n uint256 value,\n uint256 deadline,\n uint8 v,\n bytes32 r,\n bytes32 s\n ) external;\n\n function mint(address to, uint256 amount) external;\n\n function checkpointedTotalSupplyDuring(uint256 week) external returns (uint256);\n\n function checkpoint() external;\n}\n"
},
"contracts/libraries/DateUtils.sol": {
"content": "// SPDX-License-Identifier: BUSL-1.1\n\npragma solidity ^0.8.17;\n\nuint256 constant WEEK = 1 weeks;\n\nlibrary DateUtils {\n function toWeekNumber(uint256 timestamp) internal pure returns (uint256) {\n return timestamp / WEEK;\n }\n\n function toTimestamp(uint256 weekNumber) internal pure returns (uint256) {\n return weekNumber * WEEK;\n }\n}\n"
},
"@openzeppelin/contracts/access/Ownable.sol": {
"content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)\n\npragma solidity ^0.8.0;\n\nimport \"../utils/Context.sol\";\n\n/**\n * @dev Contract module which provides a basic access control mechanism, where\n * there is an account (an owner) that can be granted exclusive access to\n * specific functions.\n *\n * By default, the owner account will be the one that deploys the contract. This\n * can later be changed with {transferOwnership}.\n *\n * This module is used through inheritance. It will make available the modifier\n * `onlyOwner`, which can be applied to your functions to restrict their use to\n * the owner.\n */\nabstract contract Ownable is Context {\n address private _owner;\n\n event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);\n\n /**\n * @dev Initializes the contract setting the deployer as the initial owner.\n */\n constructor() {\n _transferOwnership(_msgSender());\n }\n\n /**\n * @dev Throws if called by any account other than the owner.\n */\n modifier onlyOwner() {\n _checkOwner();\n _;\n }\n\n /**\n * @dev Returns the address of the current owner.\n */\n function owner() public view virtual returns (address) {\n return _owner;\n }\n\n /**\n * @dev Throws if the sender is not the owner.\n */\n function _checkOwner() internal view virtual {\n require(owner() == _msgSender(), \"Ownable: caller is not the owner\");\n }\n\n /**\n * @dev Leaves the contract without owner. It will not be possible to call\n * `onlyOwner` functions anymore. Can only be called by the current owner.\n *\n * NOTE: Renouncing ownership will leave the contract without an owner,\n * thereby removing any functionality that is only available to the owner.\n */\n function renounceOwnership() public virtual onlyOwner {\n _transferOwnership(address(0));\n }\n\n /**\n * @dev Transfers ownership of the contract to a new account (`newOwner`).\n * Can only be called by the current owner.\n */\n function transferOwnership(address newOwner) public virtual onlyOwner {\n require(newOwner != address(0), \"Ownable: new owner is the zero address\");\n _transferOwnership(newOwner);\n }\n\n /**\n * @dev Transfers ownership of the contract to a new account (`newOwner`).\n * Internal function without access restriction.\n */\n function _transferOwnership(address newOwner) internal virtual {\n address oldOwner = _owner;\n _owner = newOwner;\n emit OwnershipTransferred(oldOwner, newOwner);\n }\n}\n"
},
"@openzeppelin/contracts/token/ERC20/ERC20.sol": {
"content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/ERC20.sol)\n\npragma solidity ^0.8.0;\n\nimport \"./IERC20.sol\";\nimport \"./extensions/IERC20Metadata.sol\";\nimport \"../../utils/Context.sol\";\n\n/**\n * @dev Implementation of the {IERC20} interface.\n *\n * This implementation is agnostic to the way tokens are created. This means\n * that a supply mechanism has to be added in a derived contract using {_mint}.\n * For a generic mechanism see {ERC20PresetMinterPauser}.\n *\n * TIP: For a detailed writeup see our guide\n * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How\n * to implement supply mechanisms].\n *\n * We have followed general OpenZeppelin Contracts guidelines: functions revert\n * instead returning `false` on failure. This behavior is nonetheless\n * conventional and does not conflict with the expectations of ERC20\n * applications.\n *\n * Additionally, an {Approval} event is emitted on calls to {transferFrom}.\n * This allows applications to reconstruct the allowance for all accounts just\n * by listening to said events. Other implementations of the EIP may not emit\n * these events, as it isn't required by the specification.\n *\n * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}\n * functions have been added to mitigate the well-known issues around setting\n * allowances. See {IERC20-approve}.\n */\ncontract ERC20 is Context, IERC20, IERC20Metadata {\n mapping(address => uint256) private _balances;\n\n mapping(address => mapping(address => uint256)) private _allowances;\n\n uint256 private _totalSupply;\n\n string private _name;\n string private _symbol;\n\n /**\n * @dev Sets the values for {name} and {symbol}.\n *\n * The default value of {decimals} is 18. To select a different value for\n * {decimals} you should overload it.\n *\n * All two of these values are immutable: they can only be set once during\n * construction.\n */\n constructor(string memory name_, string memory symbol_) {\n _name = name_;\n _symbol = symbol_;\n }\n\n /**\n * @dev Returns the name of the token.\n */\n function name() public view virtual override returns (string memory) {\n return _name;\n }\n\n /**\n * @dev Returns the symbol of the token, usually a shorter version of the\n * name.\n */\n function symbol() public view virtual override returns (string memory) {\n return _symbol;\n }\n\n /**\n * @dev Returns the number of decimals used to get its user representation.\n * For example, if `decimals` equals `2`, a balance of `505` tokens should\n * be displayed to a user as `5.05` (`505 / 10 ** 2`).\n *\n * Tokens usually opt for a value of 18, imitating the relationship between\n * Ether and Wei. This is the value {ERC20} uses, unless this function is\n * overridden;\n *\n * NOTE: This information is only used for _display_ purposes: it in\n * no way affects any of the arithmetic of the contract, including\n * {IERC20-balanceOf} and {IERC20-transfer}.\n */\n function decimals() public view virtual override returns (uint8) {\n return 18;\n }\n\n /**\n * @dev See {IERC20-totalSupply}.\n */\n function totalSupply() public view virtual override returns (uint256) {\n return _totalSupply;\n }\n\n /**\n * @dev See {IERC20-balanceOf}.\n */\n function balanceOf(address account) public view virtual override returns (uint256) {\n return _balances[account];\n }\n\n /**\n * @dev See {IERC20-transfer}.\n *\n * Requirements:\n *\n * - `to` cannot be the zero address.\n * - the caller must have a balance of at least `amount`.\n */\n function transfer(address to, uint256 amount) public virtual override returns (bool) {\n address owner = _msgSender();\n _transfer(owner, to, amount);\n return true;\n }\n\n /**\n * @dev See {IERC20-allowance}.\n */\n function allowance(address owner, address spender) public view virtual override returns (uint256) {\n return _allowances[owner][spender];\n }\n\n /**\n * @dev See {IERC20-approve}.\n *\n * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on\n * `transferFrom`. This is semantically equivalent to an infinite approval.\n *\n * Requirements:\n *\n * - `spender` cannot be the zero address.\n */\n function approve(address spender, uint256 amount) public virtual override returns (bool) {\n address owner = _msgSender();\n _approve(owner, spender, amount);\n return true;\n }\n\n /**\n * @dev See {IERC20-transferFrom}.\n *\n * Emits an {Approval} event indicating the updated allowance. This is not\n * required by the EIP. See the note at the beginning of {ERC20}.\n *\n * NOTE: Does not update the allowance if the current allowance\n * is the maximum `uint256`.\n *\n * Requirements:\n *\n * - `from` and `to` cannot be the zero address.\n * - `from` must have a balance of at least `amount`.\n * - the caller must have allowance for ``from``'s tokens of at least\n * `amount`.\n */\n function transferFrom(\n address from,\n address to,\n uint256 amount\n ) public virtual override returns (bool) {\n address spender = _msgSender();\n _spendAllowance(from, spender, amount);\n _transfer(from, to, amount);\n return true;\n }\n\n /**\n * @dev Atomically increases the allowance granted to `spender` by the caller.\n *\n * This is an alternative to {approve} that can be used as a mitigation for\n * problems described in {IERC20-approve}.\n *\n * Emits an {Approval} event indicating the updated allowance.\n *\n * Requirements:\n *\n * - `spender` cannot be the zero address.\n */\n function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {\n address owner = _msgSender();\n _approve(owner, spender, allowance(owner, spender) + addedValue);\n return true;\n }\n\n /**\n * @dev Atomically decreases the allowance granted to `spender` by the caller.\n *\n * This is an alternative to {approve} that can be used as a mitigation for\n * problems described in {IERC20-approve}.\n *\n * Emits an {Approval} event indicating the updated allowance.\n *\n * Requirements:\n *\n * - `spender` cannot be the zero address.\n * - `spender` must have allowance for the caller of at least\n * `subtractedValue`.\n */\n function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {\n address owner = _msgSender();\n uint256 currentAllowance = allowance(owner, spender);\n require(currentAllowance >= subtractedValue, \"ERC20: decreased allowance below zero\");\n unchecked {\n _approve(owner, spender, currentAllowance - subtractedValue);\n }\n\n return true;\n }\n\n /**\n * @dev Moves `amount` of tokens from `from` to `to`.\n *\n * This internal function is equivalent to {transfer}, and can be used to\n * e.g. implement automatic token fees, slashing mechanisms, etc.\n *\n * Emits a {Transfer} event.\n *\n * Requirements:\n *\n * - `from` cannot be the zero address.\n * - `to` cannot be the zero address.\n * - `from` must have a balance of at least `amount`.\n */\n function _transfer(\n address from,\n address to,\n uint256 amount\n ) internal virtual {\n require(from != address(0), \"ERC20: transfer from the zero address\");\n require(to != address(0), \"ERC20: transfer to the zero address\");\n\n _beforeTokenTransfer(from, to, amount);\n\n uint256 fromBalance = _balances[from];\n require(fromBalance >= amount, \"ERC20: transfer amount exceeds balance\");\n unchecked {\n _balances[from] = fromBalance - amount;\n // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by\n // decrementing then incrementing.\n _balances[to] += amount;\n }\n\n emit Transfer(from, to, amount);\n\n _afterTokenTransfer(from, to, amount);\n }\n\n /** @dev Creates `amount` tokens and assigns them to `account`, increasing\n * the total supply.\n *\n * Emits a {Transfer} event with `from` set to the zero address.\n *\n * Requirements:\n *\n * - `account` cannot be the zero address.\n */\n function _mint(address account, uint256 amount) internal virtual {\n require(account != address(0), \"ERC20: mint to the zero address\");\n\n _beforeTokenTransfer(address(0), account, amount);\n\n _totalSupply += amount;\n unchecked {\n // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.\n _balances[account] += amount;\n }\n emit Transfer(address(0), account, amount);\n\n _afterTokenTransfer(address(0), account, amount);\n }\n\n /**\n * @dev Destroys `amount` tokens from `account`, reducing the\n * total supply.\n *\n * Emits a {Transfer} event with `to` set to the zero address.\n *\n * Requirements:\n *\n * - `account` cannot be the zero address.\n * - `account` must have at least `amount` tokens.\n */\n function _burn(address account, uint256 amount) internal virtual {\n require(account != address(0), \"ERC20: burn from the zero address\");\n\n _beforeTokenTransfer(account, address(0), amount);\n\n uint256 accountBalance = _balances[account];\n require(accountBalance >= amount, \"ERC20: burn amount exceeds balance\");\n unchecked {\n _balances[account] = accountBalance - amount;\n // Overflow not possible: amount <= accountBalance <= totalSupply.\n _totalSupply -= amount;\n }\n\n emit Transfer(account, address(0), amount);\n\n _afterTokenTransfer(account, address(0), amount);\n }\n\n /**\n * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.\n *\n * This internal function is equivalent to `approve`, and can be used to\n * e.g. set automatic allowances for certain subsystems, etc.\n *\n * Emits an {Approval} event.\n *\n * Requirements:\n *\n * - `owner` cannot be the zero address.\n * - `spender` cannot be the zero address.\n */\n function _approve(\n address owner,\n address spender,\n uint256 amount\n ) internal virtual {\n require(owner != address(0), \"ERC20: approve from the zero address\");\n require(spender != address(0), \"ERC20: approve to the zero address\");\n\n _allowances[owner][spender] = amount;\n emit Approval(owner, spender, amount);\n }\n\n /**\n * @dev Updates `owner` s allowance for `spender` based on spent `amount`.\n *\n * Does not update the allowance amount in case of infinite allowance.\n * Revert if not enough allowance is available.\n *\n * Might emit an {Approval} event.\n */\n function _spendAllowance(\n address owner,\n address spender,\n uint256 amount\n ) internal virtual {\n uint256 currentAllowance = allowance(owner, spender);\n if (currentAllowance != type(uint256).max) {\n require(currentAllowance >= amount, \"ERC20: insufficient allowance\");\n unchecked {\n _approve(owner, spender, currentAllowance - amount);\n }\n }\n }\n\n /**\n * @dev Hook that is called before any transfer of tokens. This includes\n * minting and burning.\n *\n * Calling conditions:\n *\n * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\n * will be transferred to `to`.\n * - when `from` is zero, `amount` tokens will be minted for `to`.\n * - when `to` is zero, `amount` of ``from``'s tokens will be burned.\n * - `from` and `to` are never both zero.\n *\n * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n */\n function _beforeTokenTransfer(\n address from,\n address to,\n uint256 amount\n ) internal virtual {}\n\n /**\n * @dev Hook that is called after any transfer of tokens. This includes\n * minting and burning.\n *\n * Calling conditions:\n *\n * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\n * has been transferred to `to`.\n * - when `from` is zero, `amount` tokens have been minted for `to`.\n * - when `to` is zero, `amount` of ``from``'s tokens have been burned.\n * - `from` and `to` are never both zero.\n *\n * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n */\n function _afterTokenTransfer(\n address from,\n address to,\n uint256 amount\n ) internal virtual {}\n}\n"
},
"@openzeppelin/contracts/utils/cryptography/ECDSA.sol": {
"content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.8.0) (utils/cryptography/ECDSA.sol)\n\npragma solidity ^0.8.0;\n\nimport \"../Strings.sol\";\n\n/**\n * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.\n *\n * These functions can be used to verify that a message was signed by the holder\n * of the private keys of a given address.\n */\nlibrary ECDSA {\n enum RecoverError {\n NoError,\n InvalidSignature,\n InvalidSignatureLength,\n InvalidSignatureS,\n InvalidSignatureV // Deprecated in v4.8\n }\n\n function _throwError(RecoverError error) private pure {\n if (error == RecoverError.NoError) {\n return; // no error: do nothing\n } else if (error == RecoverError.InvalidSignature) {\n revert(\"ECDSA: invalid signature\");\n } else if (error == RecoverError.InvalidSignatureLength) {\n revert(\"ECDSA: invalid signature length\");\n } else if (error == RecoverError.InvalidSignatureS) {\n revert(\"ECDSA: invalid signature 's' value\");\n }\n }\n\n /**\n * @dev Returns the address that signed a hashed message (`hash`) with\n * `signature` or error string. This address can then be used for verification purposes.\n *\n * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:\n * this function rejects them by requiring the `s` value to be in the lower\n * half order, and the `v` value to be either 27 or 28.\n *\n * IMPORTANT: `hash` _must_ be the result of a hash operation for the\n * verification to be secure: it is possible to craft signatures that\n * recover to arbitrary addresses for non-hashed data. A safe way to ensure\n * this is by receiving a hash of the original message (which may otherwise\n * be too long), and then calling {toEthSignedMessageHash} on it.\n *\n * Documentation for signature generation:\n * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]\n * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]\n *\n * _Available since v4.3._\n */\n function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {\n if (signature.length == 65) {\n bytes32 r;\n bytes32 s;\n uint8 v;\n // ecrecover takes the signature parameters, and the only way to get them\n // currently is to use assembly.\n /// @solidity memory-safe-assembly\n assembly {\n r := mload(add(signature, 0x20))\n s := mload(add(signature, 0x40))\n v := byte(0, mload(add(signature, 0x60)))\n }\n return tryRecover(hash, v, r, s);\n } else {\n return (address(0), RecoverError.InvalidSignatureLength);\n }\n }\n\n /**\n * @dev Returns the address that signed a hashed message (`hash`) with\n * `signature`. This address can then be used for verification purposes.\n *\n * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:\n * this function rejects them by requiring the `s` value to be in the lower\n * half order, and the `v` value to be either 27 or 28.\n *\n * IMPORTANT: `hash` _must_ be the result of a hash operation for the\n * verification to be secure: it is possible to craft signatures that\n * recover to arbitrary addresses for non-hashed data. A safe way to ensure\n * this is by receiving a hash of the original message (which may otherwise\n * be too long), and then calling {toEthSignedMessageHash} on it.\n */\n function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {\n (address recovered, RecoverError error) = tryRecover(hash, signature);\n _throwError(error);\n return recovered;\n }\n\n /**\n * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.\n *\n * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]\n *\n * _Available since v4.3._\n */\n function tryRecover(\n bytes32 hash,\n bytes32 r,\n bytes32 vs\n ) internal pure returns (address, RecoverError) {\n bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);\n uint8 v = uint8((uint256(vs) >> 255) + 27);\n return tryRecover(hash, v, r, s);\n }\n\n /**\n * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.\n *\n * _Available since v4.2._\n */\n function recover(\n bytes32 hash,\n bytes32 r,\n bytes32 vs\n ) internal pure returns (address) {\n (address recovered, RecoverError error) = tryRecover(hash, r, vs);\n _throwError(error);\n return recovered;\n }\n\n /**\n * @dev Overload of {ECDSA-tryRecover} that receives the `v`,\n * `r` and `s` signature fields separately.\n *\n * _Available since v4.3._\n */\n function tryRecover(\n bytes32 hash,\n uint8 v,\n bytes32 r,\n bytes32 s\n ) internal pure returns (address, RecoverError) {\n // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature\n // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines\n // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most\n // signatures from current libraries generate a unique signature with an s-value in the lower half order.\n //\n // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value\n // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or\n // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept\n // these malleable signatures as well.\n if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {\n return (address(0), RecoverError.InvalidSignatureS);\n }\n\n // If the signature is valid (and not malleable), return the signer address\n address signer = ecrecover(hash, v, r, s);\n if (signer == address(0)) {\n return (address(0), RecoverError.InvalidSignature);\n }\n\n return (signer, RecoverError.NoError);\n }\n\n /**\n * @dev Overload of {ECDSA-recover} that receives the `v`,\n * `r` and `s` signature fields separately.\n */\n function recover(\n bytes32 hash,\n uint8 v,\n bytes32 r,\n bytes32 s\n ) internal pure returns (address) {\n (address recovered, RecoverError error) = tryRecover(hash, v, r, s);\n _throwError(error);\n return recovered;\n }\n\n /**\n * @dev Returns an Ethereum Signed Message, created from a `hash`. This\n * produces hash corresponding to the one signed with the\n * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]\n * JSON-RPC method as part of EIP-191.\n *\n * See {recover}.\n */\n function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {\n // 32 is the length in bytes of hash,\n // enforced by the type signature above\n return keccak256(abi.encodePacked(\"\\x19Ethereum Signed Message:\\n32\", hash));\n }\n\n /**\n * @dev Returns an Ethereum Signed Message, created from `s`. This\n * produces hash corresponding to the one signed with the\n * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]\n * JSON-RPC method as part of EIP-191.\n *\n * See {recover}.\n */\n function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {\n return keccak256(abi.encodePacked(\"\\x19Ethereum Signed Message:\\n\", Strings.toString(s.length), s));\n }\n\n /**\n * @dev Returns an Ethereum Signed Typed Data, created from a\n * `domainSeparator` and a `structHash`. This produces hash corresponding\n * to the one signed with the\n * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]\n * JSON-RPC method as part of EIP-712.\n *\n * See {recover}.\n */\n function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {\n return keccak256(abi.encodePacked(\"\\x19\\x01\", domainSeparator, structHash));\n }\n}\n"
},
"@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol": {
"content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)\n\npragma solidity ^0.8.0;\n\nimport \"../IERC20.sol\";\n\n/**\n * @dev Interface for the optional metadata functions from the ERC20 standard.\n *\n * _Available since v4.1._\n */\ninterface IERC20Metadata is IERC20 {\n /**\n * @dev Returns the name of the token.\n */\n function name() external view returns (string memory);\n\n /**\n * @dev Returns the symbol of the token.\n */\n function symbol() external view returns (string memory);\n\n /**\n * @dev Returns the decimals places of the token.\n */\n function decimals() external view returns (uint8);\n}\n"
},
"@openzeppelin/contracts/token/ERC20/IERC20.sol": {
"content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Interface of the ERC20 standard as defined in the EIP.\n */\ninterface IERC20 {\n /**\n * @dev Emitted when `value` tokens are moved from one account (`from`) to\n * another (`to`).\n *\n * Note that `value` may be zero.\n */\n event Transfer(address indexed from, address indexed to, uint256 value);\n\n /**\n * @dev Emitted when the allowance of a `spender` for an `owner` is set by\n * a call to {approve}. `value` is the new allowance.\n */\n event Approval(address indexed owner, address indexed spender, uint256 value);\n\n /**\n * @dev Returns the amount of tokens in existence.\n */\n function totalSupply() external view returns (uint256);\n\n /**\n * @dev Returns the amount of tokens owned by `account`.\n */\n function balanceOf(address account) external view returns (uint256);\n\n /**\n * @dev Moves `amount` tokens from the caller's account to `to`.\n *\n * Returns a boolean value indicating whether the operation succeeded.\n *\n * Emits a {Transfer} event.\n */\n function transfer(address to, uint256 amount) external returns (bool);\n\n /**\n * @dev Returns the remaining number of tokens that `spender` will be\n * allowed to spend on behalf of `owner` through {transferFrom}. This is\n * zero by default.\n *\n * This value changes when {approve} or {transferFrom} are called.\n */\n function allowance(address owner, address spender) external view returns (uint256);\n\n /**\n * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.\n *\n * Returns a boolean value indicating whether the operation succeeded.\n *\n * IMPORTANT: Beware that changing an allowance with this method brings the risk\n * that someone may use both the old and the new allowance by unfortunate\n * transaction ordering. One possible solution to mitigate this race\n * condition is to first reduce the spender's allowance to 0 and set the\n * desired value afterwards:\n * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729\n *\n * Emits an {Approval} event.\n */\n function approve(address spender, uint256 amount) external returns (bool);\n\n /**\n * @dev Moves `amount` tokens from `from` to `to` using the\n * allowance mechanism. `amount` is then deducted from the caller's\n * allowance.\n *\n * Returns a boolean value indicating whether the operation succeeded.\n *\n * Emits a {Transfer} event.\n */\n function transferFrom(\n address from,\n address to,\n uint256 amount\n ) external returns (bool);\n}\n"
},
"@openzeppelin/contracts/utils/Context.sol": {
"content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n function _msgSender() internal view virtual returns (address) {\n return msg.sender;\n }\n\n function _msgData() internal view virtual returns (bytes calldata) {\n return msg.data;\n }\n}\n"
},
"@openzeppelin/contracts/utils/Strings.sol": {
"content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.8.0) (utils/Strings.sol)\n\npragma solidity ^0.8.0;\n\nimport \"./math/Math.sol\";\n\n/**\n * @dev String operations.\n */\nlibrary Strings {\n bytes16 private constant _SYMBOLS = \"0123456789abcdef\";\n uint8 private constant _ADDRESS_LENGTH = 20;\n\n /**\n * @dev Converts a `uint256` to its ASCII `string` decimal representation.\n */\n function toString(uint256 value) internal pure returns (string memory) {\n unchecked {\n uint256 length = Math.log10(value) + 1;\n string memory buffer = new string(length);\n uint256 ptr;\n /// @solidity memory-safe-assembly\n assembly {\n ptr := add(buffer, add(32, length))\n }\n while (true) {\n ptr--;\n /// @solidity memory-safe-assembly\n assembly {\n mstore8(ptr, byte(mod(value, 10), _SYMBOLS))\n }\n value /= 10;\n if (value == 0) break;\n }\n return buffer;\n }\n }\n\n /**\n * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.\n */\n function toHexString(uint256 value) internal pure returns (string memory) {\n unchecked {\n return toHexString(value, Math.log256(value) + 1);\n }\n }\n\n /**\n * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.\n */\n function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {\n bytes memory buffer = new bytes(2 * length + 2);\n buffer[0] = \"0\";\n buffer[1] = \"x\";\n for (uint256 i = 2 * length + 1; i > 1; --i) {\n buffer[i] = _SYMBOLS[value & 0xf];\n value >>= 4;\n }\n require(value == 0, \"Strings: hex length insufficient\");\n return string(buffer);\n }\n\n /**\n * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.\n */\n function toHexString(address addr) internal pure returns (string memory) {\n return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);\n }\n}\n"
},
"@openzeppelin/contracts/utils/math/Math.sol": {
"content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/Math.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Standard math utilities missing in the Solidity language.\n */\nlibrary Math {\n enum Rounding {\n Down, // Toward negative infinity\n Up, // Toward infinity\n Zero // Toward zero\n }\n\n /**\n * @dev Returns the largest of two numbers.\n */\n function max(uint256 a, uint256 b) internal pure returns (uint256) {\n return a > b ? a : b;\n }\n\n /**\n * @dev Returns the smallest of two numbers.\n */\n function min(uint256 a, uint256 b) internal pure returns (uint256) {\n return a < b ? a : b;\n }\n\n /**\n * @dev Returns the average of two numbers. The result is rounded towards\n * zero.\n */\n function average(uint256 a, uint256 b) internal pure returns (uint256) {\n // (a + b) / 2 can overflow.\n return (a & b) + (a ^ b) / 2;\n }\n\n /**\n * @dev Returns the ceiling of the division of two numbers.\n *\n * This differs from standard division with `/` in that it rounds up instead\n * of rounding down.\n */\n function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {\n // (a + b - 1) / b can overflow on addition, so we distribute.\n return a == 0 ? 0 : (a - 1) / b + 1;\n }\n\n /**\n * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0\n * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)\n * with further edits by Uniswap Labs also under MIT license.\n */\n function mulDiv(\n uint256 x,\n uint256 y,\n uint256 denominator\n ) internal pure returns (uint256 result) {\n unchecked {\n // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use\n // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256\n // variables such that product = prod1 * 2^256 + prod0.\n uint256 prod0; // Least significant 256 bits of the product\n uint256 prod1; // Most significant 256 bits of the product\n assembly {\n let mm := mulmod(x, y, not(0))\n prod0 := mul(x, y)\n prod1 := sub(sub(mm, prod0), lt(mm, prod0))\n }\n\n // Handle non-overflow cases, 256 by 256 division.\n if (prod1 == 0) {\n return prod0 / denominator;\n }\n\n // Make sure the result is less than 2^256. Also prevents denominator == 0.\n require(denominator > prod1);\n\n ///////////////////////////////////////////////\n // 512 by 256 division.\n ///////////////////////////////////////////////\n\n // Make division exact by subtracting the remainder from [prod1 prod0].\n uint256 remainder;\n assembly {\n // Compute remainder using mulmod.\n remainder := mulmod(x, y, denominator)\n\n // Subtract 256 bit number from 512 bit number.\n prod1 := sub(prod1, gt(remainder, prod0))\n prod0 := sub(prod0, remainder)\n }\n\n // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.\n // See https://cs.stackexchange.com/q/138556/92363.\n\n // Does not overflow because the denominator cannot be zero at this stage in the function.\n uint256 twos = denominator & (~denominator + 1);\n assembly {\n // Divide denominator by twos.\n denominator := div(denominator, twos)\n\n // Divide [prod1 prod0] by twos.\n prod0 := div(prod0, twos)\n\n // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.\n twos := add(div(sub(0, twos), twos), 1)\n }\n\n // Shift in bits from prod1 into prod0.\n prod0 |= prod1 * twos;\n\n // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such\n // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for\n // four bits. That is, denominator * inv = 1 mod 2^4.\n uint256 inverse = (3 * denominator) ^ 2;\n\n // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works\n // in modular arithmetic, doubling the correct bits in each step.\n inverse *= 2 - denominator * inverse; // inverse mod 2^8\n inverse *= 2 - denominator * inverse; // inverse mod 2^16\n inverse *= 2 - denominator * inverse; // inverse mod 2^32\n inverse *= 2 - denominator * inverse; // inverse mod 2^64\n inverse *= 2 - denominator * inverse; // inverse mod 2^128\n inverse *= 2 - denominator * inverse; // inverse mod 2^256\n\n // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.\n // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is\n // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1\n // is no longer required.\n result = prod0 * inverse;\n return result;\n }\n }\n\n /**\n * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.\n */\n function mulDiv(\n uint256 x,\n uint256 y,\n uint256 denominator,\n Rounding rounding\n ) internal pure returns (uint256) {\n uint256 result = mulDiv(x, y, denominator);\n if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {\n result += 1;\n }\n return result;\n }\n\n /**\n * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.\n *\n * Inspired by Henry S. Warren, Jr.'s \"Hacker's Delight\" (Chapter 11).\n */\n function sqrt(uint256 a) internal pure returns (uint256) {\n if (a == 0) {\n return 0;\n }\n\n // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.\n //\n // We know that the \"msb\" (most significant bit) of our target number `a` is a power of 2 such that we have\n // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.\n //\n // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`\n // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`\n // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`\n //\n // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.\n uint256 result = 1 << (log2(a) >> 1);\n\n // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,\n // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at\n // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision\n // into the expected uint128 result.\n unchecked {\n result = (result + a / result) >> 1;\n result = (result + a / result) >> 1;\n result = (result + a / result) >> 1;\n result = (result + a / result) >> 1;\n result = (result + a / result) >> 1;\n result = (result + a / result) >> 1;\n result = (result + a / result) >> 1;\n return min(result, a / result);\n }\n }\n\n /**\n * @notice Calculates sqrt(a), following the selected rounding direction.\n */\n function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {\n unchecked {\n uint256 result = sqrt(a);\n return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);\n }\n }\n\n /**\n * @dev Return the log in base 2, rounded down, of a positive value.\n * Returns 0 if given 0.\n */\n function log2(uint256 value) internal pure returns (uint256) {\n uint256 result = 0;\n unchecked {\n if (value >> 128 > 0) {\n value >>= 128;\n result += 128;\n }\n if (value >> 64 > 0) {\n value >>= 64;\n result += 64;\n }\n if (value >> 32 > 0) {\n value >>= 32;\n result += 32;\n }\n if (value >> 16 > 0) {\n value >>= 16;\n result += 16;\n }\n if (value >> 8 > 0) {\n value >>= 8;\n result += 8;\n }\n if (value >> 4 > 0) {\n value >>= 4;\n result += 4;\n }\n if (value >> 2 > 0) {\n value >>= 2;\n result += 2;\n }\n if (value >> 1 > 0) {\n result += 1;\n }\n }\n return result;\n }\n\n /**\n * @dev Return the log in base 2, following the selected rounding direction, of a positive value.\n * Returns 0 if given 0.\n */\n function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {\n unchecked {\n uint256 result = log2(value);\n return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);\n }\n }\n\n /**\n * @dev Return the log in base 10, rounded down, of a positive value.\n * Returns 0 if given 0.\n */\n function log10(uint256 value) internal pure returns (uint256) {\n uint256 result = 0;\n