Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./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 defaut 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
* overloaded;
*
* 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");
_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");
_approve(_msgSender(), spender, currentAllowance - subtractedValue);
return true;
}
/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(address sender, address recipient, uint256 amount) internal 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");
_balances[sender] = senderBalance - amount;
_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 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);
}
/**
* @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");
_balances[account] = accountBalance - amount;
_totalSupply -= amount;
emit Transfer(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 to 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 { }
}
// 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.
*/
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;
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() {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), 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() external virtual onlyOwner {
_renounceOwnership();
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) external virtual onlyOwner {
require(
newOwner != address(0),
"Ownable: new owner is the zero address"
);
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
function _renounceOwnership() private {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./utils/ContextUpgradeable.sol";
import "./utils/Initializable.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 OwnableUpgradeableWithExpiry is Initializable, ContextUpgradeable {
address private _owner;
uint256 private _deployTimestamp;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
function __Ownable_init() internal initializer {
__Context_init_unchained();
__Ownable_init_unchained();
}
function __Ownable_init_unchained() internal initializer {
address msgSender = _msgSender();
_owner = msgSender;
_deployTimestamp = block.timestamp;
emit OwnershipTransferred(address(0), 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() external virtual onlyOwner {
_renounceOwnership();
}
/**
* @dev Get the timestamp of ownership expiry.
* @return The timestamp of ownership expiry.
*/
function getOwnershipExpiryTimestamp() public view returns (uint256) {
return _deployTimestamp + 82 weeks;
}
/**
* @dev Check if the contract ownership is expired.
* @return True if the contract ownership is expired.
*/
function isOwnershipExpired() public view returns (bool) {
return block.timestamp > getOwnershipExpiryTimestamp();
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called after ownership is expired.
*/
function renounceOwnershipAfterExpiry() external {
require(isOwnershipExpired(), "Ownership not yet expired");
_renounceOwnership();
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) external virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
function _renounceOwnership() private {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
uint256[49] private __gap;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using Address for address;
function safeTransfer(IERC20 token, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(IERC20 token, address spender, uint256 value) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
// solhint-disable-next-line max-line-length
require((value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender) + value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
uint256 newAllowance = oldAllowance - value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) { // Return data is optional
// solhint-disable-next-line max-line-length
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*
* TIP: If you would like to learn more about reentrancy and alternative ways
* to protect against it, check out our blog post
* https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
*/
abstract contract ReentrancyGuard {
// Booleans are more expensive than uint256 or any type that takes up a full
// word because each write operation emits an extra SLOAD to first read the
// slot's contents, replace the bits taken up by the boolean, and then write
// back. This is the compiler's defense against contract upgrades and
// pointer aliasing, and it cannot be disabled.
// The values being non-zero value makes deployment a bit more expensive,
// but in exchange the refund on every call to nonReentrant will be lower in
// amount. Since refunds are capped to a percentage of the total
// transaction's gas, it is best to keep them low in cases like this one, to
// increase the likelihood of the full refund coming into effect.
uint256 private constant _NOT_ENTERED = 1;
uint256 private constant _ENTERED = 2;
uint256 private _status;
constructor () {
_status = _NOT_ENTERED;
}
/**
* @dev Prevents a contract from calling itself, directly or indirectly.
* Calling a `nonReentrant` function from another `nonReentrant`
* function is not supported. It is possible to prevent this from happening
* by making the `nonReentrant` function external, and make it call a
* `private` function that does the actual work.
*/
modifier nonReentrant() {
// On the first call to nonReentrant, _notEntered will be true
require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
_;
// By storing the original value once again, a refund is triggered (see
// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on 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;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.delegatecall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// 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) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./Initializable.sol";
/*
* @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 ContextUpgradeable is Initializable {
function __Context_init() internal initializer {
__Context_init_unchained();
}
function __Context_init_unchained() internal initializer {
}
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
uint256[50] private __gap;
}
// SPDX-License-Identifier: MIT
// solhint-disable-next-line compiler-version
pragma solidity ^0.8.0;
import "./Address.sol";
/**
* @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
* behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
* external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
* function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
*
* TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
* possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
*
* CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
* that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
*/
abstract contract Initializable {
/**
* @dev Indicates that the contract has been initialized.
*/
bool private _initialized;
/**
* @dev Indicates that the contract is in the process of being initialized.
*/
bool private _initializing;
/**
* @dev Modifier to protect an initializer function from being invoked twice.
*/
modifier initializer() {
require(_initializing || !_initialized, "Initializable: contract is already initialized");
bool isTopLevelCall = !_initializing;
if (isTopLevelCall) {
_initializing = true;
_initialized = true;
}
_;
if (isTopLevelCall) {
_initializing = false;
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./ContextUpgradeable.sol";
/**
* @dev Contract module which allows children to implement an emergency stop
* mechanism that can be triggered by an authorized account.
*
* This module is used through inheritance. It will make available the
* modifiers `whenNotPaused` and `whenPaused`, which can be applied to
* the functions of your contract. Note that they will not be pausable by
* simply including this module, only once the modifiers are put in place.
*/
abstract contract Pausable is ContextUpgradeable {
/**
* @dev Emitted when the pause is triggered by `account`.
*/
event Paused(address account);
/**
* @dev Emitted when the pause is lifted by `account`.
*/
event Unpaused(address account);
bool private _paused;
/**
* @dev Initializes the contract in unpaused state.
*/
constructor() {
_paused = false;
}
/**
* @dev Returns true if the contract is paused, and false otherwise.
*/
function paused() public view virtual returns (bool) {
return _paused;
}
/**
* @dev Modifier to make a function callable only when the contract is not paused.
*
* Requirements:
*
* - The contract must not be paused.
*/
modifier whenNotPaused() {
require(!paused(), "Pausable: paused");
_;
}
/**
* @dev Modifier to make a function callable only when the contract is paused.
*
* Requirements:
*
* - The contract must be paused.
*/
modifier whenPaused() {
require(paused(), "Pausable: not paused");
_;
}
/**
* @dev Triggers stopped state.
*
* Requirements:
*
* - The contract must not be paused.
*/
function _pause() internal virtual whenNotPaused {
_paused = true;
emit Paused(_msgSender());
}
/**
* @dev Returns to normal state.
*
* Requirements:
*
* - The contract must be paused.
*/
function _unpause() internal virtual whenPaused {
_paused = false;
emit Unpaused(_msgSender());
}
}
// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;
import "./@openzeppelin/contracts/ERC20.sol";
import "./@openzeppelin/contracts/Ownable.sol";
contract CosmosERC20 is ERC20, Ownable {
uint8 private immutable _decimals;
constructor(
string memory name_,
string memory symbol_,
uint8 decimals_
) ERC20(name_, symbol_) {
_decimals = decimals_;
}
function decimals() public view virtual override returns (uint8) {
return _decimals;
}
function mint(address account, uint256 amount) public onlyOwner {
_mint(account, amount);
}
function burn(address account, uint256 amount) public onlyOwner {
_burn(account, amount);
}
}
// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;
import "./@openzeppelin/contracts/IERC20.sol";
import "./@openzeppelin/contracts/SafeERC20.sol";
import "./@openzeppelin/contracts/utils/Address.sol";
import "./@openzeppelin/contracts/utils/Initializable.sol";
import "./@openzeppelin/contracts/utils/Pausable.sol";
import "./@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "./CosmosToken.sol";
import "./@openzeppelin/contracts/OwnableUpgradeableWithExpiry.sol";
// This is used purely to avoid stack too deep errors
// represents everything about a given validator set
struct ValsetArgs {
// the validators in this set, represented by an Ethereum address
address[] validators;
// the powers of the given validators in the same order as above
uint256[] powers;
// the nonce of this validator set
uint256 valsetNonce;
// the reward amount denominated in the below reward token, can be
// set to zero
uint256 rewardAmount;
// the reward token, should be set to the zero address if not being used
address rewardToken;
}
// Don't change the order of state for working upgrades.
// AND BE AWARE OF INHERITANCE VARIABLES!
// Inherited contracts contain storage slots and must be accounted for in any upgrades
// always test an exact upgrade on testnet and localhost before mainnet upgrades.
contract Peggy is
Initializable,
OwnableUpgradeableWithExpiry,
Pausable,
ReentrancyGuard
{
using SafeERC20 for IERC20;
// ⚠️ ONLY APPEND TO STATE VARIABLES AND DON'T CHANGE VARIABLE ORDER/DEFINITIONS INCL NOT MAKING THEM IMMUTABLE ⚠️
// These are updated often
bytes32 public state_lastValsetCheckpoint;
mapping(address => uint256) public state_lastBatchNonces;
mapping(bytes32 => uint256) public state_invalidationMapping;
uint256 public state_lastValsetNonce = 0;
uint256 public state_lastEventNonce = 0;
// These are set once at initialization
bytes32 public state_peggyId;
uint256 public state_powerThreshold;
mapping(address => bool) public isHeliosNativeToken;
uint256 private constant MAX_NONCE_JUMP_LIMIT = 10_000_000_000_000;
// TransactionBatchExecutedEvent and SendToHeliosEvent both include the field _eventNonce.
// This is incremented every time one of these events is emitted. It is checked by the
// Cosmos module to ensure that all events are received in order, and that none are lost.
//
// ValsetUpdatedEvent does not include the field _eventNonce because it is never submitted to the Cosmos
// module. It is purely for the use of relayers to allow them to successfully submit batches.
event TransactionBatchExecutedEvent(
uint256 indexed _batchNonce,
address indexed _token,
uint256 _eventNonce
);
event SendToHeliosEvent(
address indexed _tokenContract,
address indexed _sender,
bytes32 indexed _destination,
uint256 _amount,
uint256 _eventNonce,
string _data
);
event ERC20DeployedEvent(
string _cosmosDenom,
address indexed _tokenContract,
string _name,
string _symbol,
uint8 _decimals,
uint256 _eventNonce
);
event ValsetUpdatedEvent(
uint256 indexed _newValsetNonce,
uint256 _eventNonce,
uint256 _rewardAmount,
address _rewardToken,
address[] _validators,
uint256[] _powers
);
function _validateValidatorSet(
address[] calldata _validators,
uint256[] calldata _powers,
uint256 _powerThreshold
) private pure {
// Check that validators and powers set is well-formed
require(
_validators.length == _powers.length,
"Malformed current validator set"
);
// Check cumulative power to ensure the contract has sufficient power to actually
// pass a vote
uint256 cumulativePower = 0;
for (uint256 i = 0; i < _powers.length; i++) {
cumulativePower = cumulativePower + _powers[i];
if (cumulativePower > _powerThreshold) {
break;
}
}
require(
cumulativePower > _powerThreshold,
"Submitted validator set signatures do not have enough power."
);
}
function initialize(
// A unique identifier for this peggy instance to use in signatures
bytes32 _peggyId,
// How much voting power is needed to approve operations
uint256 _powerThreshold,
// The validator set, not in valset args format since many of it's
// arguments would never be used in this case
address[] calldata _validators,
uint256[] calldata _powers
) external initializer {
__Context_init_unchained();
__Ownable_init_unchained();
// CHECKS
_validateValidatorSet(_validators, _powers, _powerThreshold);
ValsetArgs memory _valset;
_valset = ValsetArgs(_validators, _powers, 0, 0, address(0));
bytes32 newCheckpoint = makeCheckpoint(_valset, _peggyId);
// ACTIONS
state_peggyId = _peggyId;
state_powerThreshold = _powerThreshold;
state_lastValsetCheckpoint = newCheckpoint;
state_lastEventNonce = state_lastEventNonce + 1;
// LOGS
emit ValsetUpdatedEvent(
state_lastValsetNonce,
state_lastEventNonce,
0,
address(0),
_validators,
_powers
);
}
function lastBatchNonce(
address _erc20Address
) public view returns (uint256) {
return state_lastBatchNonces[_erc20Address];
}
// Utility function to verify geth style signatures
function verifySig(
address _signer,
bytes32 _theHash,
uint8 _v,
bytes32 _r,
bytes32 _s
) private pure returns (bool) {
bytes32 messageDigest = keccak256(
abi.encodePacked("\x19Ethereum Signed Message:\n32", _theHash)
);
return _signer == ecrecover(messageDigest, _v, _r, _s);
}
// Make a new checkpoint from the supplied validator set
// A checkpoint is a hash of all relevant information about the valset. This is stored by the contract,
// instead of storing the information directly. This saves on storage and gas.
// The format of the checkpoint is:
// h(peggyId, "checkpoint", valsetNonce, validators[], powers[])
// Where h is the keccak256 hash function.
// The validator powers must be decreasing or equal. This is important for checking the signatures on the
// next valset, since it allows the caller to stop verifying signatures once a quorum of signatures have been verified.
function makeCheckpoint(
ValsetArgs memory _valsetArgs,
bytes32 _peggyId
) private pure returns (bytes32) {
// bytes32 encoding of the string "checkpoint"
bytes32 methodName = 0x636865636b706f696e7400000000000000000000000000000000000000000000;
bytes32 checkpoint = keccak256(
abi.encode(
_peggyId,
methodName,
_valsetArgs.valsetNonce,
_valsetArgs.validators,
_valsetArgs.powers,
_valsetArgs.rewardAmount,
_valsetArgs.rewardToken
)
);
return checkpoint;
}
function checkValidatorSignatures(
// The current validator set and their powers
address[] memory _currentValidators,
uint256[] memory _currentPowers,
// The current validator's signatures
uint8[] memory _v,
bytes32[] memory _r,
bytes32[] memory _s,
// This is what we are checking they have signed
bytes32 _theHash,
uint256 _powerThreshold
) private pure {
uint256 cumulativePower = 0;
for (uint256 i = 0; i < _currentValidators.length; i++) {
// If v is set to 0, this signifies that it was not possible to get a signature from this validator and we skip evaluation
// (In a valid signature, it is either 27 or 28)
if (_v[i] != 0) {
// Check that the current validator has signed off on the hash
require(
verifySig(
_currentValidators[i],
_theHash,
_v[i],
_r[i],
_s[i]
),
"Validator signature does not match."
);
// Sum up cumulative power
cumulativePower = cumulativePower + _currentPowers[i];
// Break early to avoid wasting gas
if (cumulativePower > _powerThreshold) {
break;
}
}
}
// Check that there was enough power
require(
cumulativePower > _powerThreshold,
"Submitted validator set signatures do not have enough power."
);
// Success
}
// This updates the valset by checking that the validators in the current valset have signed off on the
// new valset. The signatures supplied are the signatures of the current valset over the checkpoint hash
// generated from the new valset.
// Anyone can call this function, but they must supply valid signatures of state_powerThreshold of the current valset over
// the new valset.
function updateValset(
// The new version of the validator set
ValsetArgs calldata _newValset,
// The current validators that approve the change
ValsetArgs calldata _currentValset,
// These are arrays of the parts of the current validator's signatures
uint8[] calldata _v,
bytes32[] calldata _r,
bytes32[] calldata _s
) external whenNotPaused {
// CHECKS
// Check that the valset nonce is greater than the old one
require(
_newValset.valsetNonce > _currentValset.valsetNonce,
"New valset nonce must be greater than the current nonce"
);
// Check that current validators, powers, and signatures (v,r,s) set is well-formed
require(
_currentValset.validators.length == _currentValset.powers.length &&
_currentValset.validators.length == _v.length &&
_currentValset.validators.length == _r.length &&
_currentValset.validators.length == _s.length,
"Malformed current validator set"
);
// Prevent insane jumps potentially leaving the contract unable to process further valset updates
require(
_newValset.valsetNonce <
_currentValset.valsetNonce + MAX_NONCE_JUMP_LIMIT,
"New valset nonce must be less than 10_000_000_000_000 greater than the current nonce"
);
// Check that the supplied current validator set matches the saved checkpoint
require(
makeCheckpoint(_currentValset, state_peggyId) ==
state_lastValsetCheckpoint,
"Supplied current validators and powers do not match checkpoint."
);
// Check that enough current validators have signed off on the new validator set
bytes32 newCheckpoint = makeCheckpoint(_newValset, state_peggyId);
checkValidatorSignatures(
_currentValset.validators,
_currentValset.powers,
_v,
_r,
_s,
newCheckpoint,
state_powerThreshold
);
_validateValidatorSet(
_newValset.validators,
_newValset.powers,
state_powerThreshold
);
// ACTIONS
// Stored to be used next time to validate that the valset
// supplied by the caller is correct.
state_lastValsetCheckpoint = newCheckpoint;
// Store new nonce
state_lastValsetNonce = _newValset.valsetNonce;
// Send submission reward to msg.sender if reward token is a valid value
if (
_newValset.rewardToken != address(0) && _newValset.rewardAmount != 0
) {
IERC20(_newValset.rewardToken).safeTransfer(
msg.sender,
_newValset.rewardAmount
);
}
// LOGS
state_lastEventNonce = state_lastEventNonce + 1;
emit ValsetUpdatedEvent(
_newValset.valsetNonce,
state_lastEventNonce,
_newValset.rewardAmount,
_newValset.rewardToken,
_newValset.validators,
_newValset.powers
);
}
// submitBatch processes a batch of Cosmos -> Ethereum transactions by sending the tokens in the transactions
// to the destination addresses. It is approved by the current Cosmos validator set.
// Anyone can call this function, but they must supply valid signatures of state_powerThreshold of the current valset over
// the batch.
function submitBatch(
// The validators that approve the batch
ValsetArgs memory _currentValset,
// These are arrays of the parts of the validators signatures
uint8[] memory _v,
bytes32[] memory _r,
bytes32[] memory _s,
// The batch of transactions
uint256[] memory _amounts,
address[] memory _destinations,
uint256[] memory _fees,
uint256 _batchNonce,
address _tokenContract,
// a block height beyond which this batch is not valid
// used to provide a fee-free timeout
uint256 _batchTimeout
) external nonReentrant whenNotPaused {
// CHECKS scoped to reduce stack depth
{
// Check that the batch nonce is higher than the last nonce for this token
require(
state_lastBatchNonces[_tokenContract] < _batchNonce,
"New batch nonce must be greater than the current nonce"
);
// Prevent insane jumps potentially leaving the contract unable to process further batches
require(
_batchNonce <
state_lastBatchNonces[_tokenContract] +
MAX_NONCE_JUMP_LIMIT,
"New batch nonce must be less than 10_000_000_000_000 greater than the current nonce"
);
// Check that the block height is less than the timeout height
require(
block.number < _batchTimeout,
"Batch timeout must be greater than the current block height"
);
// Check that current validators, powers, and signatures (v,r,s) set is well-formed
require(
_currentValset.validators.length ==
_currentValset.powers.length &&
_currentValset.validators.length == _v.length &&
_currentValset.validators.length == _r.length &&
_currentValset.validators.length == _s.length,
"Malformed current validator set"
);
// Check that the supplied current validator set matches the saved checkpoint
require(
makeCheckpoint(_currentValset, state_peggyId) ==
state_lastValsetCheckpoint,
"Supplied current validators and powers do not match checkpoint."
);
// Check that the transaction batch is well-formed
require(
_amounts.length == _destinations.length &&
_amounts.length == _fees.length,
"Malformed batch of transactions"
);
// Check that enough current validators have signed off on the transaction batch and valset
checkValidatorSignatures(
_currentValset.validators,
_currentValset.powers,
_v,
_r,
_s,
// Get hash of the transaction batch and checkpoint
keccak256(
abi.encode(
state_peggyId,
// bytes32 encoding of "transactionBatch"
0x7472616e73616374696f6e426174636800000000000000000000000000000000,
_amounts,
_destinations,
_fees,
_batchNonce,
_tokenContract,
_batchTimeout
)
),
state_powerThreshold
);
// ACTIONS
// Store batch nonce
state_lastBatchNonces[_tokenContract] = _batchNonce;
{
// Send transaction amounts to destinations
uint256 totalFee;
for (uint256 i = 0; i < _amounts.length; i++) {
if (isHeliosNativeToken[_tokenContract]) {
CosmosERC20(_tokenContract).mint(
_destinations[i],
_amounts[i]
);
} else {
IERC20(_tokenContract).safeTransfer(
_destinations[i],
_amounts[i]
);
}
totalFee = totalFee + _fees[i];
}
if (totalFee > 0) {
// Send transaction fees to msg.sender
IERC20(_tokenContract).safeTransfer(msg.sender, totalFee);
}
}
}
// LOGS scoped to reduce stack depth
{
state_lastEventNonce = state_lastEventNonce + 1;
emit TransactionBatchExecutedEvent(
_batchNonce,
_tokenContract,
state_lastEventNonce
);
}
}
function sendToHelios(
address _tokenContract,
bytes32 _destination,
uint256 _amount,
string calldata _data
) external whenNotPaused nonReentrant {
uint256 transferAmount;
if (isHeliosNativeToken[_tokenContract]) {
CosmosERC20(_tokenContract).burn(msg.sender, _amount);
transferAmount = _amount;
} else {
uint256 balanceBeforeTransfer = IERC20(_tokenContract).balanceOf(
address(this)
);
IERC20(_tokenContract).safeTransferFrom(
msg.sender,
address(this),
_amount
);
uint256 balanceAfterTransfer = IERC20(_tokenContract).balanceOf(
address(this)
);
transferAmount = balanceAfterTransfer - balanceBeforeTransfer;
}
state_lastEventNonce = state_lastEventNonce + 1;
emit SendToHeliosEvent(
_tokenContract,
msg.sender,
_destination,
transferAmount,
state_lastEventNonce,
_data
);
}
function deployERC20(
string calldata _cosmosDenom,
string calldata _name,
string calldata _symbol,
uint8 _decimals
) external {
CosmosERC20 erc20 = new CosmosERC20(_name, _symbol, _decimals);
isHeliosNativeToken[address(erc20)] = true;
// Fire an event to let the Cosmos module know
state_lastEventNonce = state_lastEventNonce + 1;
emit ERC20DeployedEvent(
_cosmosDenom,
address(erc20),
_name,
_symbol,
_decimals,
state_lastEventNonce
);
}
function emergencyPause() external onlyOwner {
_pause();
}
function emergencyUnpause() external onlyOwner {
_unpause();
}
}
