Contract Source Code:
// SPDX-License-Identifier: MIT AND AGPL-3.0-or-later
pragma solidity =0.8.9;
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "../shared/ProtocolConstants.sol";
import "../interfaces/tokens/IUSDV.sol";
import "../interfaces/tokens/IVader.sol";
import "../interfaces/tokens/vesting/ILinearVesting.sol";
import "../interfaces/tokens/converter/IConverter.sol";
/**
* @dev Implementation of the {IVader} interface.
*
* The Vader token that acts as the backbone of the Vader protocol,
* burned and minted to mint and burn USDV tokens respectively.
*
* The token has a fixed initial supply at 25 billion units that is meant to then
* fluctuate depending on the amount of USDV minted into and burned from circulation.
*
* Emissions are initially controlled by the Vader team and then will be governed
* by the DAO.
*/
contract Vader is IVader, ProtocolConstants, ERC20, Ownable {
/* ========== STATE VARIABLES ========== */
// The Vader <-> Vether converter contract
IConverter public converter;
// The Vader Team vesting contract
ILinearVesting public vest;
// The USDV contract, used to apply proper access control
IUSDV public usdv;
// The initial maximum supply of the token, equivalent to 25 bn units
uint256 public maxSupply = _INITIAL_VADER_SUPPLY;
/* ========== CONSTRUCTOR ========== */
/**
* @dev Mints the ecosystem growth fund and grant allocation amount described in the whitepaper to the
* token contract itself.
*
* As the token is meant to be minted and burned freely between USDV and itself,
* there is no real initialization taking place apart from the initially minted
* supply for the following components:
*
* - Grant Allocation: The amount of funds meant to be distributed by the DAO as grants to expand the protocol
*
* - Ecosystem Growth: An allocation that is released to strategic partners for the
* protocol's expansion
*
* The latter two of the allocations are minted at a later date given that the addresses of
* the converter and vesting contract are not known on deployment.
*/
constructor() ERC20("Vader", "VADER") {
_mint(address(this), _GRANT_ALLOCATION);
_mint(address(this), _ECOSYSTEM_GROWTH);
}
/* ========== MUTATIVE FUNCTIONS ========== */
/**
* @dev Creates a manual emission event
*
* Emits an {Emission} event indicating the amount emitted as well as what the current
* era's timestamp is.
*/
function createEmission(address user, uint256 amount)
external
override
onlyOwner
{
_transfer(address(this), user, amount);
emit Emission(user, amount);
}
/* ========== RESTRICTED FUNCTIONS ========== */
/**
* @dev Sets the initial {converter} and {vest} contract addresses. Additionally, mints
* the Vader amount available for conversion as well as the team allocation that is meant
* to be vested to each respective contract.
*
* Emits a {ProtocolInitialized} event indicating all the supplied values of the function.
*
* Requirements:
*
* - the caller must be the deployer of the contract
* - the contract must not have already been initialized
*/
function setComponents(
IConverter _converter,
ILinearVesting _vest,
address[] calldata vesters,
uint192[] calldata amounts
) external onlyOwner {
require(
_converter != IConverter(_ZERO_ADDRESS) &&
_vest != ILinearVesting(_ZERO_ADDRESS),
"Vader::setComponents: Incorrect Arguments"
);
require(
converter == IConverter(_ZERO_ADDRESS),
"Vader::setComponents: Already Set"
);
converter = _converter;
vest = _vest;
_mint(address(_converter), _VETH_ALLOCATION);
_mint(address(_vest), _TEAM_ALLOCATION);
_vest.begin(vesters, amounts);
emit ProtocolInitialized(
address(_converter),
address(_vest)
);
}
/**
* @dev Set USDV
* Emits a {USDVSet} event indicating that USDV is set
*
* Requirements:
*
* - the caller must be owner
* - USDV must be of a non-zero address
* - USDV must not be set
*/
function setUSDV(IUSDV _usdv) external onlyOwner {
require(_usdv != IUSDV(_ZERO_ADDRESS), "Vader::setUSDV: Invalid USDV address");
require(usdv == IUSDV(_ZERO_ADDRESS), "Vader::setUSDV: USDV already set");
usdv = _usdv;
emit USDVSet(address(_usdv));
}
/**
* @dev Allows a strategic partnership grant to be claimed.
*
* Emits a {GrantClaimed} event indicating the beneficiary of the grant as
* well as the grant amount.
*
* Requirements:
*
* - the caller must be the DAO
* - the token must hold sufficient Vader allocation for the grant
* - the grant must be of a non-zero amount
*/
function claimGrant(address beneficiary, uint256 amount) external onlyOwner {
require(amount != 0, "Vader::claimGrant: Non-Zero Amount Required");
emit GrantClaimed(beneficiary, amount);
_transfer(address(this), beneficiary, amount);
}
/**
* @dev Allows the maximum supply of the token to be adjusted.
*
* Emits an {MaxSupplyChanged} event indicating the previous and next maximum
* total supplies.
*
* Requirements:
*
* - the caller must be the DAO
* - the new maximum supply must be greater than the current supply
*/
function adjustMaxSupply(uint256 _maxSupply) external onlyOwner {
require(
_maxSupply >= totalSupply(),
"Vader::adjustMaxSupply: Max supply cannot subcede current supply"
);
emit MaxSupplyChanged(maxSupply, _maxSupply);
maxSupply = _maxSupply;
}
/**
* @dev Allows the USDV token to perform mints of VADER tokens
*
* Emits an ERC-20 {Transfer} event signaling the minting operation.
*
* Requirements:
*
* - the caller must be the USDV
* - the new supply must be below the maximum supply
*/
function mint(address _user, uint256 _amount) external onlyUSDV {
require(
maxSupply >= totalSupply() + _amount,
"Vader::mint: Max supply reached"
);
_mint(_user, _amount);
}
/**
* @dev Allows the USDV token to perform burns of VADER tokens
*
* Emits an ERC-20 {Transfer} event signaling the burning operation.
*
* Requirements:
*
* - the caller must be the USDV
* - the USDV contract must have a sufficient VADER balance
*/
function burn(uint256 _amount) external onlyUSDV {
_burn(msg.sender, _amount);
}
/* ========== INTERNAL FUNCTIONS ========== */
/* ========== PRIVATE FUNCTIONS ========== */
/**
* @dev Ensures only the USDV is able to invoke a particular function by validating that the
* contract has been set up and that the msg.sender is the USDV address
*/
function _onlyUSDV() private view {
require(
address(usdv) == msg.sender,
"Vader::_onlyUSDV: Insufficient Privileges"
);
}
/* ========== MODIFIERS ========== */
/**
* @dev Throws if invoked by anyone else other than the USDV
*/
modifier onlyUSDV() {
_onlyUSDV();
_;
}
}
// SPDX-License-Identifier: MIT AND AGPL-3.0-or-later
pragma solidity =0.8.9;
abstract contract ProtocolConstants {
/* ========== GENERAL ========== */
// The zero address, utility
address internal constant _ZERO_ADDRESS = address(0);
// One year, utility
uint256 internal constant _ONE_YEAR = 365 days;
// Basis Points
uint256 internal constant _MAX_BASIS_POINTS = 100_00;
/* ========== VADER TOKEN ========== */
// Max VADER supply
uint256 internal constant _INITIAL_VADER_SUPPLY = 25_000_000_000 * 1 ether;
// Allocation for VETH holders
uint256 internal constant _VETH_ALLOCATION = 7_500_000_000 * 1 ether;
// Team allocation vested over {VESTING_DURATION} years
uint256 internal constant _TEAM_ALLOCATION = 2_500_000_000 * 1 ether;
// Ecosystem growth fund unlocked for partnerships & USDV provision
uint256 internal constant _ECOSYSTEM_GROWTH = 2_500_000_000 * 1 ether;
// Total grant tokens
uint256 internal constant _GRANT_ALLOCATION = 12_500_000_000 * 1 ether;
// Emission Era
uint256 internal constant _EMISSION_ERA = 24 hours;
// Initial Emission Curve, 5
uint256 internal constant _INITIAL_EMISSION_CURVE = 5;
// Fee Basis Points
uint256 internal constant _MAX_FEE_BASIS_POINTS = 1_00;
/* ========== VESTING ========== */
// Vesting Duration
uint256 internal constant _VESTING_DURATION = 2 * _ONE_YEAR;
/* ========== CONVERTER ========== */
// Vader -> Vether Conversion Rate (1000:1)
uint256 internal constant _VADER_VETHER_CONVERSION_RATE = 10_000;
// Burn Address
address internal constant _BURN =
0xdeaDDeADDEaDdeaDdEAddEADDEAdDeadDEADDEaD;
/* ========== SWAP QUEUE ========== */
// A minimum of 10 swaps will be executed per block
uint256 internal constant _MIN_SWAPS_EXECUTED = 10;
// Expressed in basis points (50%)
uint256 internal constant _DEFAULT_SWAPS_EXECUTED = 50_00;
// The queue size of each block is 100 units
uint256 internal constant _QUEUE_SIZE = 100;
/* ========== GAS QUEUE ========== */
// Address of Chainlink Fast Gas Price Oracle
address internal constant _FAST_GAS_ORACLE =
0x169E633A2D1E6c10dD91238Ba11c4A708dfEF37C;
/* ========== VADER RESERVE ========== */
// Minimum delay between grants
uint256 internal constant _GRANT_DELAY = 30 days;
// Maximum grant size divisor
uint256 internal constant _MAX_GRANT_BASIS_POINTS = 10_00;
}
// SPDX-License-Identifier: MIT AND AGPL-3.0-or-later
pragma solidity =0.8.9;
interface ILinearVesting {
/* ========== STRUCTS ========== */
// Struct of a vesting member, tight-packed to 256-bits
struct Vester {
uint192 amount;
uint64 lastClaim;
uint128 start;
uint128 end;
}
/* ========== FUNCTIONS ========== */
function getClaim(address _vester)
external
view
returns (uint256 vestedAmount);
function claim() external returns (uint256 vestedAmount);
// function claimConverted() external returns (uint256 vestedAmount);
function begin(address[] calldata vesters, uint192[] calldata amounts)
external;
function vestFor(address user, uint256 amount) external;
/* ========== EVENTS ========== */
event VestingInitialized(uint256 duration);
event VestingCreated(address user, uint256 amount);
event Vested(address indexed from, uint256 amount);
}
// SPDX-License-Identifier: MIT AND AGPL-3.0-or-later
pragma solidity =0.8.9;
interface IConverter {
/* ========== FUNCTIONS ========== */
function convert(bytes32[] calldata proof, uint256 amount, uint256 minVader)
external
returns (uint256 vaderReceived);
/* ========== EVENTS ========== */
event Conversion(
address indexed user,
uint256 vetherAmount,
uint256 vaderAmount
);
}
// SPDX-License-Identifier: MIT AND AGPL-3.0-or-later
pragma solidity =0.8.9;
interface IVader {
/* ========== FUNCTIONS ========== */
function createEmission(address user, uint256 amount) external;
/* ========== EVENTS ========== */
event Emission(address to, uint256 amount);
event EmissionChanged(uint256 previous, uint256 next);
event MaxSupplyChanged(uint256 previous, uint256 next);
event GrantClaimed(address indexed beneficiary, uint256 amount);
event ProtocolInitialized(
address converter,
address vest
);
event USDVSet(address usdv);
/* ========== DEPRECATED ========== */
// function getCurrentEraEmission() external view returns (uint256);
// function getEraEmission(uint256 currentSupply)
// external
// view
// returns (uint256);
// function calculateFee() external view returns (uint256 basisPoints);
}
// SPDX-License-Identifier: MIT AND AGPL-3.0-or-later
pragma solidity =0.8.9;
interface IUSDV {
/* ========== STRUCTS ========== */
/* ========== FUNCTIONS ========== */
/* ========== EVENTS ========== */
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/
interface IERC20Metadata is IERC20 {
/**
* @dev Returns the name of the token.
*/
function name() external view returns (string memory);
/**
* @dev Returns the symbol of the token.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the decimals places of the token.
*/
function decimals() external view returns (uint8);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev 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";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin Contracts guidelines: functions revert
* instead returning `false` on failure. This behavior is nonetheless
* conventional and does not conflict with the expectations of ERC20
* applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
/**
* @dev Sets the values for {name} and {symbol}.
*
* The default value of {decimals} is 18. To select a different value for
* {decimals} you should overload it.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5.05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless this function is
* overridden;
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view virtual override returns (uint8) {
return 18;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* Requirements:
*
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for ``sender``'s tokens of at least
* `amount`.
*/
function transferFrom(
address sender,
address recipient,
uint256 amount
) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
uint256 currentAllowance = _allowances[sender][_msgSender()];
require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
unchecked {
_approve(sender, _msgSender(), currentAllowance - amount);
}
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
uint256 currentAllowance = _allowances[_msgSender()][spender];
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(_msgSender(), spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `sender` to `recipient`.
*
* This internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(
address sender,
address recipient,
uint256 amount
) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
uint256 senderBalance = _balances[sender];
require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[sender] = senderBalance - amount;
}
_balances[recipient] += amount;
emit Transfer(sender, recipient, amount);
_afterTokenTransfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply += amount;
_balances[account] += amount;
emit Transfer(address(0), account, amount);
_afterTokenTransfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
}
_totalSupply -= amount;
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(
address owner,
address spender,
uint256 amount
) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _afterTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
abstract contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() {
_setOwner(_msgSender());
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
_setOwner(address(0));
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
_setOwner(newOwner);
}
function _setOwner(address newOwner) private {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}