Contract Name:
FullFeatureToken
Contract Source Code:
// SPDX-License-Identifier: GPL-3.0
pragma solidity 0.8.7;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Pausable.sol";
import { Helpers } from "./lib/Helpers.sol";
contract FullFeatureToken is ERC20, ERC20Burnable, ERC20Pausable, Ownable {
/// @notice mapping of blacklisted addresses to a boolean
mapping(address => bool) private _isBlacklisted;
/// @notice mapping of whitelisted addresses to a boolean
mapping(address => bool) public whitelist;
/// @notice array holding all whitelisted addresses
address[] public whitelistedAddresses;
/// @notice support for attaching of documentation for security tokens
string public initialDocumentUri;
/// @notice the security token documentation
string public documentUri;
/// @notice initial number of tokens which will be minted during initialization
uint256 public immutable initialSupply;
/// @notice initial max amount of tokens allowed per wallet
uint256 public immutable initialMaxTokenAmountPerAddress;
/// @notice max amount of tokens allowed per wallet
uint256 public maxTokenAmountPerAddress;
/// @notice set of features supported by the token
struct ERC20ConfigProps {
bool _isMintable;
bool _isBurnable;
bool _isPausable;
bool _isBlacklistEnabled;
bool _isDocumentAllowed;
bool _isWhitelistEnabled;
bool _isMaxAmountOfTokensSet;
bool _isForceTransferAllowed;
}
/// @notice features of the token
ERC20ConfigProps private configProps;
/// @notice owner of the contract
address public immutable initialTokenOwner;
/// @notice number of decimals of the token
uint8 private immutable _decimals;
/// @notice emitted when an address is blacklisted
event UserBlacklisted(address indexed addr);
/// @notice emitted when an address is unblacklisted
event UserUnBlacklisted(address indexed addr);
/// @notice emitted when a new document is set for the security token
event DocumentUriSet(string newDocUri);
/// @notice emitted when a new max amount of tokens per wallet is set
event MaxTokenAmountPerSet(uint256 newMaxTokenAmount);
/// @notice emitted when a new whitelist is set
event UsersWhitelisted(address[] updatedAddresses);
/// @notice raised when the amount sent is zero
error InvalidMaxTokenAmount(uint256 maxTokenAmount);
/// @notice raised when the decimals are not in the range 0 - 18
error InvalidDecimals(uint8 decimals);
/// @notice raised when setting maxTokenAmount less than current
error MaxTokenAmountPerAddrLtPrevious();
/// @notice raised when blacklisting is not enabled
error BlacklistNotEnabled();
/// @notice raised when the address is already blacklisted
error AddrAlreadyBlacklisted(address addr);
/// @notice raised when the address is already unblacklisted
error AddrAlreadyUnblacklisted(address addr);
/// @notice raised when attempting to blacklist a whitelisted address
error CannotBlacklistWhitelistedAddr(address addr);
/// @notice raised when a recipient address is blacklisted
error RecipientBlacklisted(address addr);
/// @notice raised when a sender address is blacklisted
error SenderBlacklisted(address addr);
/// @notice raised when a recipient address is not whitelisted
error RecipientNotWhitelisted(address addr);
/// @notice raised when a sender address is not whitelisted
error SenderNotWhitelisted(address addr);
/// @notice raised when recipient balance exceeds maxTokenAmountPerAddress
error DestBalanceExceedsMaxAllowed(address addr);
/// @notice raised minting is not enabled
error MintingNotEnabled();
/// @notice raised when burning is not enabled
error BurningNotEnabled();
/// @notice raised when pause is not enabled
error PausingNotEnabled();
/// @notice raised when whitelist is not enabled
error WhitelistNotEnabled();
/// @notice raised when attempting to whitelist a blacklisted address
error CannotWhitelistBlacklistedAddr(address addr);
/// @notice raised when trying to set a document URI when not allowed
error DocumentUriNotAllowed();
/**
* @notice modifier for validating if transfer is possible and valid
* @param sender the sender of the transaction
* @param recipient the recipient of the transaction
*/
modifier validateTransfer(address sender, address recipient) {
if (isWhitelistEnabled()) {
if (!whitelist[sender]) {
revert SenderNotWhitelisted(sender);
}
if (!whitelist[recipient]) {
revert RecipientNotWhitelisted(recipient);
}
}
if (isBlacklistEnabled()) {
if (_isBlacklisted[sender]) {
revert SenderBlacklisted(sender);
}
if (_isBlacklisted[recipient]) {
revert RecipientBlacklisted(recipient);
}
}
_;
}
constructor(
string memory name_,
string memory symbol_,
uint256 initialSupplyToSet,
uint8 decimalsToSet,
address tokenOwner,
ERC20ConfigProps memory customConfigProps,
uint256 maxTokenAmount,
string memory newDocumentUri
) ERC20(name_, symbol_) {
if (customConfigProps._isMaxAmountOfTokensSet) {
if (maxTokenAmount == 0) {
revert InvalidMaxTokenAmount(maxTokenAmount);
}
}
if (decimalsToSet > 18) {
revert InvalidDecimals(decimalsToSet);
}
Helpers.validateAddress(tokenOwner);
initialSupply = initialSupplyToSet;
initialMaxTokenAmountPerAddress = maxTokenAmount;
initialDocumentUri = newDocumentUri;
initialTokenOwner = tokenOwner;
_decimals = decimalsToSet;
configProps = customConfigProps;
documentUri = newDocumentUri;
maxTokenAmountPerAddress = maxTokenAmount;
if (initialSupplyToSet != 0) {
_mint(tokenOwner, initialSupplyToSet * 10**decimalsToSet);
}
if (tokenOwner != msg.sender) {
transferOwnership(tokenOwner);
}
}
/**
* @notice hook called before any transfer of tokens. This includes minting and burning
* imposed by the ERC20 standard
* @param from - address of the sender
* @param to - address of the recipient
* @param amount - amount of tokens to transfer
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual override(ERC20, ERC20Pausable) {
super._beforeTokenTransfer(from, to, amount);
}
/// @notice method which checks if the token is pausable
function isPausable() public view returns (bool) {
return configProps._isPausable;
}
/// @notice method which checks if the token is mintable
function isMintable() public view returns (bool) {
return configProps._isMintable;
}
/// @notice method which checks if the token is burnable
function isBurnable() public view returns (bool) {
return configProps._isBurnable;
}
/// @notice method which checks if the token supports blacklisting
function isBlacklistEnabled() public view returns (bool) {
return configProps._isBlacklistEnabled;
}
/// @notice method which checks if the token supports whitelisting
function isWhitelistEnabled() public view returns (bool) {
return configProps._isWhitelistEnabled;
}
/// @notice method which checks if the token supports max amount of tokens per wallet
function isMaxAmountOfTokensSet() public view returns (bool) {
return configProps._isMaxAmountOfTokensSet;
}
/// @notice method which checks if the token supports documentUris
function isDocumentUriAllowed() public view returns (bool) {
return configProps._isDocumentAllowed;
}
/// @notice method which checks if the token supports force transfers
function isForceTransferAllowed() public view returns (bool) {
return configProps._isForceTransferAllowed;
}
/// @notice method which returns the number of decimals for the token
function decimals() public view virtual override returns (uint8) {
return _decimals;
}
/**
* @notice which returns an array of all the whitelisted addresses
* @return whitelistedAddresses array of all the whitelisted addresses
*/
function getWhitelistedAddresses() external view returns (address[] memory) {
return whitelistedAddresses;
}
/**
* @notice method which allows the owner to set a documentUri
* @param newDocumentUri - the new documentUri
* @dev only callable by the owner
*/
function setDocumentUri(string memory newDocumentUri) external onlyOwner {
if (!isDocumentUriAllowed()) {
revert DocumentUriNotAllowed();
}
documentUri = newDocumentUri;
emit DocumentUriSet(newDocumentUri);
}
/**
* @notice method which allows the owner to set a max amount of tokens per wallet
* @param newMaxTokenAmount - the new max amount of tokens per wallet
* @dev only callable by the owner
*/
function setMaxTokenAmountPerAddress(uint256 newMaxTokenAmount)
external
onlyOwner
{
if (newMaxTokenAmount <= maxTokenAmountPerAddress) {
revert MaxTokenAmountPerAddrLtPrevious();
}
maxTokenAmountPerAddress = newMaxTokenAmount;
emit MaxTokenAmountPerSet(newMaxTokenAmount);
}
/**
* @notice method which allows the owner to blacklist an address
* @param addr - the address to blacklist
* @dev only callable by the owner
* @dev only callable if the token is not paused
* @dev only callable if the token supports blacklisting
* @dev only callable if the address is not already blacklisted
* @dev only callable if the address is not whitelisted
*/
function blackList(address addr) external onlyOwner whenNotPaused {
Helpers.validateAddress(addr);
if (!isBlacklistEnabled()) {
revert BlacklistNotEnabled();
}
if (_isBlacklisted[addr]) {
revert AddrAlreadyBlacklisted(addr);
}
if (isWhitelistEnabled() && whitelist[addr]) {
revert CannotBlacklistWhitelistedAddr(addr);
}
_isBlacklisted[addr] = true;
emit UserBlacklisted(addr);
}
/**
* @notice method which allows the owner to unblacklist an address
* @param addr - the address to unblacklist
* @dev only callable by the owner
* @dev only callable if the token is not paused
* @dev only callable if the token supports blacklisting
* @dev only callable if the address is blacklisted
*/
function removeFromBlacklist(address addr) external onlyOwner whenNotPaused {
Helpers.validateAddress(addr);
if (!isBlacklistEnabled()) {
revert BlacklistNotEnabled();
}
if (!_isBlacklisted[addr]) {
revert AddrAlreadyUnblacklisted(addr);
}
_isBlacklisted[addr] = false;
emit UserUnBlacklisted(addr);
}
/**
* @notice method which allows to transfer a predefined amount of tokens to a predefined address
* @param to - the address to transfer the tokens to
* @param amount - the amount of tokens to transfer
* @return true if the transfer was successful
* @dev only callable if the token is not paused
* @dev only callable if the balance of the receiver is lower than the max amount of tokens per wallet
* @dev checks if blacklisting is enabled and if the sender and receiver are not blacklisted
* @dev checks if whitelisting is enabled and if the sender and receiver are whitelisted
*/
function transfer(address to, uint256 amount)
public
virtual
override
whenNotPaused
validateTransfer(msg.sender, to)
returns (bool)
{
if (isMaxAmountOfTokensSet()) {
if (balanceOf(to) + amount > maxTokenAmountPerAddress) {
revert DestBalanceExceedsMaxAllowed(to);
}
}
return super.transfer(to, amount);
}
/**
* @notice method which allows to transfer a predefined amount of tokens from a predefined address to a predefined address
* @param from - the address to transfer the tokens from
* @param to - the address to transfer the tokens to
* @param amount - the amount of tokens to transfer
* @return true if the transfer was successful
* @dev only callable if the token is not paused
* @dev only callable if the balance of the receiver is lower than the max amount of tokens per wallet
* @dev checks if blacklisting is enabled and if the sender and receiver are not blacklisted
* @dev checks if whitelisting is enabled and if the sender and receiver are whitelisted
*/
function transferFrom(
address from,
address to,
uint256 amount
)
public
virtual
override
whenNotPaused
validateTransfer(from, to)
returns (bool)
{
if (isMaxAmountOfTokensSet()) {
if (balanceOf(to) + amount > maxTokenAmountPerAddress) {
revert DestBalanceExceedsMaxAllowed(to);
}
}
if (isForceTransferAllowed() && owner() == msg.sender) {
_transfer(from, to, amount);
return true;
} else {
return super.transferFrom(from, to, amount);
}
}
/**
* @notice method which allows to mint a predefined amount of tokens to a predefined address
* @param to - the address to mint the tokens to
* @param amount - the amount of tokens to mint
* @dev only callable by the owner
* @dev only callable if the token is not paused
* @dev only callable if the token supports additional minting
* @dev only callable if the balance of the receiver is lower than the max amount of tokens per wallet
* @dev checks if blacklisting is enabled and if the receiver is not blacklisted
* @dev checks if whitelisting is enabled and if the receiver is whitelisted
*/
function mint(address to, uint256 amount) external onlyOwner whenNotPaused {
if (!isMintable()) {
revert MintingNotEnabled();
}
if (isMaxAmountOfTokensSet()) {
if (balanceOf(to) + amount > maxTokenAmountPerAddress) {
revert DestBalanceExceedsMaxAllowed(to);
}
}
if (isBlacklistEnabled()) {
if (_isBlacklisted[to]) {
revert RecipientBlacklisted(to);
}
}
if (isWhitelistEnabled()) {
if (!whitelist[to]) {
revert RecipientNotWhitelisted(to);
}
}
super._mint(to, amount);
}
/**
* @notice method which allows to burn a predefined amount of tokens
* @param amount - the amount of tokens to burn
* @dev only callable by the owner
* @dev only callable if the token is not paused
* @dev only callable if the token supports burning
*/
function burn(uint256 amount) public override onlyOwner whenNotPaused {
if (!isBurnable()) {
revert BurningNotEnabled();
}
super.burn(amount);
}
/**
* @notice method which allows to burn a predefined amount of tokens from a predefined address
* @param from - the address to burn the tokens from
* @param amount - the amount of tokens to burn
* @dev only callable by the owner
* @dev only callable if the token is not paused
* @dev only callable if the token supports burning
*/
function burnFrom(address from, uint256 amount)
public
override
onlyOwner
whenNotPaused
{
if (!isBurnable()) {
revert BurningNotEnabled();
}
super.burnFrom(from, amount);
}
/**
* @notice method which allows to pause the token
* @dev only callable by the owner
*/
function pause() external onlyOwner {
if (!isPausable()) {
revert PausingNotEnabled();
}
_pause();
}
/**
* @notice method which allows to unpause the token
* @dev only callable by the owner
*/
function unpause() external onlyOwner {
if (!isPausable()) {
revert PausingNotEnabled();
}
_unpause();
}
/**
* @notice method which allows to removing the owner of the token
* @dev methods which are only callable by the owner will not be callable anymore
* @dev only callable by the owner
* @dev only callable if the token is not paused
*/
function renounceOwnership() public override onlyOwner whenNotPaused {
super.renounceOwnership();
}
/**
* @notice method which allows to transfer the ownership of the token
* @param newOwner - the address of the new owner
* @dev only callable by the owner
* @dev only callable if the token is not paused
*/
function transferOwnership(address newOwner)
public
override
onlyOwner
whenNotPaused
{
super.transferOwnership(newOwner);
}
/**
* @notice method which allows to update the whitelist of the token
* @param updatedAddresses - the new set of addresses
* @dev only callable by the owner
* @dev only callable if the token supports whitelisting
*/
function updateWhitelist(address[] calldata updatedAddresses)
external
onlyOwner
{
if (!isWhitelistEnabled()) {
revert WhitelistNotEnabled();
}
_clearWhitelist();
_addManyToWhitelist(updatedAddresses);
whitelistedAddresses = updatedAddresses;
emit UsersWhitelisted(updatedAddresses);
}
/**
* @notice method which allows for adding a new set of addresses to the whitelist
* @param addresses - the addresses to add to the whitelist
* @dev called internally by the contract
* @dev only callable if any of the addresses are not already whitelisted
*/
function _addManyToWhitelist(address[] calldata addresses) private {
for (uint256 i; i < addresses.length; ) {
Helpers.validateAddress(addresses[i]);
if (configProps._isBlacklistEnabled && _isBlacklisted[addresses[i]]) {
revert CannotWhitelistBlacklistedAddr(addresses[i]);
}
whitelist[addresses[i]] = true;
unchecked {
++i;
}
}
}
/**
* @notice method which allows for removing a set of addresses from the whitelist
*/
function _clearWhitelist() private {
unchecked {
address[] memory addresses = whitelistedAddresses;
for (uint256 i; i < addresses.length; i++) {
whitelist[addresses[i]] = false;
}
}
}
}
// SPDX-License-Identifier: GPL-3.0
pragma solidity 0.8.7;
library Helpers {
/// @notice raised when an address is zero
error NonZeroAddress(address addr);
/// @notice raised when payment fails
error PaymentFailed(address to, uint256 amount);
/**
* @notice Helper function to check if an address is a zero address
* @param addr - address to check
*/
function validateAddress(address addr) internal pure {
if (addr == address(0x0)) {
revert NonZeroAddress(addr);
}
}
/**
* @notice method to pay a specific address with a specific amount
* @dev inspired from https://github.com/transmissions11/solmate/blob/main/src/utils/SafeTransferLib.sol
* @param to - the address to pay
* @param amount - the amount to pay
*/
function safeTransferETH(address to, uint256 amount) internal {
bool success;
// solhint-disable-next-line no-inline-assembly
assembly {
// Transfer the ETH and store if it succeeded or not.
success := call(gas(), to, amount, 0, 0, 0, 0)
}
if (!success) {
revert PaymentFailed(to, amount);
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)
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() {
_transferOwnership(_msgSender());
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
_checkOwner();
_;
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if the sender is not the owner.
*/
function _checkOwner() internal view virtual {
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 {
_transferOwnership(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");
_transferOwnership(newOwner);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Internal function without access restriction.
*/
function _transferOwnership(address newOwner) internal virtual {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/ERC20.sol)
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:
*
* - `to` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address to, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_transfer(owner, to, 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}.
*
* NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
* `transferFrom`. This is semantically equivalent to an infinite approval.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_approve(owner, 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}.
*
* NOTE: Does not update the allowance if the current allowance
* is the maximum `uint256`.
*
* Requirements:
*
* - `from` and `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
* - the caller must have allowance for ``from``'s tokens of at least
* `amount`.
*/
function transferFrom(
address from,
address to,
uint256 amount
) public virtual override returns (bool) {
address spender = _msgSender();
_spendAllowance(from, spender, amount);
_transfer(from, to, 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) {
address owner = _msgSender();
_approve(owner, spender, allowance(owner, 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) {
address owner = _msgSender();
uint256 currentAllowance = allowance(owner, spender);
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `from` to `to`.
*
* 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:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
*/
function _transfer(
address from,
address to,
uint256 amount
) internal virtual {
require(from != address(0), "ERC20: transfer from the zero address");
require(to != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(from, to, amount);
uint256 fromBalance = _balances[from];
require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[from] = fromBalance - amount;
}
_balances[to] += amount;
emit Transfer(from, to, amount);
_afterTokenTransfer(from, to, 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 Updates `owner` s allowance for `spender` based on spent `amount`.
*
* Does not update the allowance amount in case of infinite allowance.
* Revert if not enough allowance is available.
*
* Might emit an {Approval} event.
*/
function _spendAllowance(
address owner,
address spender,
uint256 amount
) internal virtual {
uint256 currentAllowance = allowance(owner, spender);
if (currentAllowance != type(uint256).max) {
require(currentAllowance >= amount, "ERC20: insufficient allowance");
unchecked {
_approve(owner, spender, currentAllowance - 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
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/extensions/ERC20Burnable.sol)
pragma solidity ^0.8.0;
import "../ERC20.sol";
import "../../../utils/Context.sol";
/**
* @dev Extension of {ERC20} that allows token holders to destroy both their own
* tokens and those that they have an allowance for, in a way that can be
* recognized off-chain (via event analysis).
*/
abstract contract ERC20Burnable is Context, ERC20 {
/**
* @dev Destroys `amount` tokens from the caller.
*
* See {ERC20-_burn}.
*/
function burn(uint256 amount) public virtual {
_burn(_msgSender(), amount);
}
/**
* @dev Destroys `amount` tokens from `account`, deducting from the caller's
* allowance.
*
* See {ERC20-_burn} and {ERC20-allowance}.
*
* Requirements:
*
* - the caller must have allowance for ``accounts``'s tokens of at least
* `amount`.
*/
function burnFrom(address account, uint256 amount) public virtual {
_spendAllowance(account, _msgSender(), amount);
_burn(account, amount);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/ERC20Pausable.sol)
pragma solidity ^0.8.0;
import "../ERC20.sol";
import "../../../security/Pausable.sol";
/**
* @dev ERC20 token with pausable token transfers, minting and burning.
*
* Useful for scenarios such as preventing trades until the end of an evaluation
* period, or having an emergency switch for freezing all token transfers in the
* event of a large bug.
*/
abstract contract ERC20Pausable is ERC20, Pausable {
/**
* @dev See {ERC20-_beforeTokenTransfer}.
*
* Requirements:
*
* - the contract must not be paused.
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual override {
super._beforeTokenTransfer(from, to, amount);
require(!paused(), "ERC20Pausable: token transfer while paused");
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
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
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @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);
/**
* @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 `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, 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 `from` to `to` 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 from,
address to,
uint256 amount
) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
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
// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.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 Context {
/**
* @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 Modifier to make a function callable only when the contract is not paused.
*
* Requirements:
*
* - The contract must not be paused.
*/
modifier whenNotPaused() {
_requireNotPaused();
_;
}
/**
* @dev Modifier to make a function callable only when the contract is paused.
*
* Requirements:
*
* - The contract must be paused.
*/
modifier whenPaused() {
_requirePaused();
_;
}
/**
* @dev Returns true if the contract is paused, and false otherwise.
*/
function paused() public view virtual returns (bool) {
return _paused;
}
/**
* @dev Throws if the contract is paused.
*/
function _requireNotPaused() internal view virtual {
require(!paused(), "Pausable: paused");
}
/**
* @dev Throws if the contract is not paused.
*/
function _requirePaused() internal view virtual {
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());
}
}