// SPDX-License-Identifier: MIT
// File: contracts/AddressChecksumStringUtil.sol
pragma solidity ^0.8.0;
// Derived from https://ethereum.stackexchange.com/a/63953, no license specified
// Modified to remove unnecessary functionality and prepend the checksummed string address with "0x"
/**
* @dev This contract provides a set of pure functions for computing the EIP-55
* checksum of an account in formats friendly to both off-chain and on-chain
* callers, as well as for checking if a given string hex representation of an
* address has a valid checksum. These helper functions could also be repurposed
* as a library that extends the `address` type.
*/
contract AddressChecksumStringUtil {
function toChecksumString(address account) internal pure returns (string memory asciiString) {
// convert the account argument from address to bytes.
bytes20 data = bytes20(account);
// create an in-memory fixed-size bytes array.
bytes memory asciiBytes = new bytes(40);
// declare variable types.
uint8 b;
uint8 leftNibble;
uint8 rightNibble;
bool leftCaps;
bool rightCaps;
uint8 asciiOffset;
// get the capitalized characters in the actual checksum.
bool[40] memory caps = _toChecksumCapsFlags(account);
// iterate over bytes, processing left and right nibble in each iteration.
for (uint256 i = 0; i < data.length; i++) {
// locate the byte and extract each nibble.
b = uint8(uint160(data) / (2**(8*(19 - i))));
leftNibble = b / 16;
rightNibble = b - 16 * leftNibble;
// locate and extract each capitalization status.
leftCaps = caps[2*i];
rightCaps = caps[2*i + 1];
// get the offset from nibble value to ascii character for left nibble.
asciiOffset = _getAsciiOffset(leftNibble, leftCaps);
// add the converted character to the byte array.
asciiBytes[2 * i] = bytes1(leftNibble + asciiOffset);
// get the offset from nibble value to ascii character for right nibble.
asciiOffset = _getAsciiOffset(rightNibble, rightCaps);
// add the converted character to the byte array.
asciiBytes[2 * i + 1] = bytes1(rightNibble + asciiOffset);
}
return string(abi.encodePacked("0x", string(asciiBytes)));
}
function _getAsciiOffset(uint8 nibble, bool caps) internal pure returns (uint8 offset) {
// to convert to ascii characters, add 48 to 0-9, 55 to A-F, & 87 to a-f.
if (nibble < 10) {
offset = 48;
} else if (caps) {
offset = 55;
} else {
offset = 87;
}
}
function _toChecksumCapsFlags(address account) internal pure returns (bool[40] memory characterCapitalized) {
// convert the address to bytes.
bytes20 a = bytes20(account);
// hash the address (used to calculate checksum).
bytes32 b = keccak256(abi.encodePacked(_toAsciiString(a)));
// declare variable types.
uint8 leftNibbleAddress;
uint8 rightNibbleAddress;
uint8 leftNibbleHash;
uint8 rightNibbleHash;
// iterate over bytes, processing left and right nibble in each iteration.
for (uint256 i; i < a.length; i++) {
// locate the byte and extract each nibble for the address and the hash.
rightNibbleAddress = uint8(a[i]) % 16;
leftNibbleAddress = (uint8(a[i]) - rightNibbleAddress) / 16;
rightNibbleHash = uint8(b[i]) % 16;
leftNibbleHash = (uint8(b[i]) - rightNibbleHash) / 16;
characterCapitalized[2 * i] = (leftNibbleAddress > 9 && leftNibbleHash > 7);
characterCapitalized[2 * i + 1] = (rightNibbleAddress > 9 && rightNibbleHash > 7);
}
}
// based on https://ethereum.stackexchange.com/a/56499/48410
function _toAsciiString(bytes20 data) internal pure returns (string memory asciiString) {
// create an in-memory fixed-size bytes array.
bytes memory asciiBytes = new bytes(40);
// declare variable types.
uint8 b;
uint8 leftNibble;
uint8 rightNibble;
// iterate over bytes, processing left and right nibble in each iteration.
for (uint256 i = 0; i < data.length; i++) {
// locate the byte and extract each nibble.
b = uint8(uint160(data) / (2 ** (8 * (19 - i))));
leftNibble = b / 16;
rightNibble = b - 16 * leftNibble;
// to convert to ascii characters, add 48 to 0-9 and 87 to a-f.
asciiBytes[2 * i] = bytes1(leftNibble + (leftNibble < 10 ? 48 : 87));
asciiBytes[2 * i + 1] = bytes1(rightNibble + (rightNibble < 10 ? 48 : 87));
}
return string(asciiBytes);
}
}
// File: @openzeppelin/contracts/security/ReentrancyGuard.sol
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)
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 making 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;
}
}
// File: @openzeppelin/contracts/utils/Strings.sol
// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)
pragma solidity ^0.8.0;
/**
* @dev String operations.
*/
library Strings {
bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
/**
* @dev Converts a `uint256` to its ASCII `string` decimal representation.
*/
function toString(uint256 value) internal pure returns (string memory) {
// Inspired by OraclizeAPI's implementation - MIT licence
// https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
if (value == 0) {
return "0";
}
uint256 temp = value;
uint256 digits;
while (temp != 0) {
digits++;
temp /= 10;
}
bytes memory buffer = new bytes(digits);
while (value != 0) {
digits -= 1;
buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
value /= 10;
}
return string(buffer);
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
*/
function toHexString(uint256 value) internal pure returns (string memory) {
if (value == 0) {
return "0x00";
}
uint256 temp = value;
uint256 length = 0;
while (temp != 0) {
length++;
temp >>= 8;
}
return toHexString(value, length);
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
*/
function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
bytes memory buffer = new bytes(2 * length + 2);
buffer[0] = "0";
buffer[1] = "x";
for (uint256 i = 2 * length + 1; i > 1; --i) {
buffer[i] = _HEX_SYMBOLS[value & 0xf];
value >>= 4;
}
require(value == 0, "Strings: hex length insufficient");
return string(buffer);
}
}
// File: @openzeppelin/contracts/utils/cryptography/ECDSA.sol
// OpenZeppelin Contracts v4.4.1 (utils/cryptography/ECDSA.sol)
pragma solidity ^0.8.0;
/**
* @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
*
* These functions can be used to verify that a message was signed by the holder
* of the private keys of a given address.
*/
library ECDSA {
enum RecoverError {
NoError,
InvalidSignature,
InvalidSignatureLength,
InvalidSignatureS,
InvalidSignatureV
}
function _throwError(RecoverError error) private pure {
if (error == RecoverError.NoError) {
return; // no error: do nothing
} else if (error == RecoverError.InvalidSignature) {
revert("ECDSA: invalid signature");
} else if (error == RecoverError.InvalidSignatureLength) {
revert("ECDSA: invalid signature length");
} else if (error == RecoverError.InvalidSignatureS) {
revert("ECDSA: invalid signature 's' value");
} else if (error == RecoverError.InvalidSignatureV) {
revert("ECDSA: invalid signature 'v' value");
}
}
/**
* @dev Returns the address that signed a hashed message (`hash`) with
* `signature` or error string. This address can then be used for verification purposes.
*
* The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
* this function rejects them by requiring the `s` value to be in the lower
* half order, and the `v` value to be either 27 or 28.
*
* IMPORTANT: `hash` _must_ be the result of a hash operation for the
* verification to be secure: it is possible to craft signatures that
* recover to arbitrary addresses for non-hashed data. A safe way to ensure
* this is by receiving a hash of the original message (which may otherwise
* be too long), and then calling {toEthSignedMessageHash} on it.
*
* Documentation for signature generation:
* - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
* - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
*
* _Available since v4.3._
*/
function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
// Check the signature length
// - case 65: r,s,v signature (standard)
// - case 64: r,vs signature (cf https://eips.ethereum.org/EIPS/eip-2098) _Available since v4.1._
if (signature.length == 65) {
bytes32 r;
bytes32 s;
uint8 v;
// ecrecover takes the signature parameters, and the only way to get them
// currently is to use assembly.
assembly {
r := mload(add(signature, 0x20))
s := mload(add(signature, 0x40))
v := byte(0, mload(add(signature, 0x60)))
}
return tryRecover(hash, v, r, s);
} else if (signature.length == 64) {
bytes32 r;
bytes32 vs;
// ecrecover takes the signature parameters, and the only way to get them
// currently is to use assembly.
assembly {
r := mload(add(signature, 0x20))
vs := mload(add(signature, 0x40))
}
return tryRecover(hash, r, vs);
} else {
return (address(0), RecoverError.InvalidSignatureLength);
}
}
/**
* @dev Returns the address that signed a hashed message (`hash`) with
* `signature`. This address can then be used for verification purposes.
*
* The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
* this function rejects them by requiring the `s` value to be in the lower
* half order, and the `v` value to be either 27 or 28.
*
* IMPORTANT: `hash` _must_ be the result of a hash operation for the
* verification to be secure: it is possible to craft signatures that
* recover to arbitrary addresses for non-hashed data. A safe way to ensure
* this is by receiving a hash of the original message (which may otherwise
* be too long), and then calling {toEthSignedMessageHash} on it.
*/
function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
(address recovered, RecoverError error) = tryRecover(hash, signature);
_throwError(error);
return recovered;
}
/**
* @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
*
* See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
*
* _Available since v4.3._
*/
function tryRecover(
bytes32 hash,
bytes32 r,
bytes32 vs
) internal pure returns (address, RecoverError) {
bytes32 s;
uint8 v;
assembly {
s := and(vs, 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff)
v := add(shr(255, vs), 27)
}
return tryRecover(hash, v, r, s);
}
/**
* @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
*
* _Available since v4.2._
*/
function recover(
bytes32 hash,
bytes32 r,
bytes32 vs
) internal pure returns (address) {
(address recovered, RecoverError error) = tryRecover(hash, r, vs);
_throwError(error);
return recovered;
}
/**
* @dev Overload of {ECDSA-tryRecover} that receives the `v`,
* `r` and `s` signature fields separately.
*
* _Available since v4.3._
*/
function tryRecover(
bytes32 hash,
uint8 v,
bytes32 r,
bytes32 s
) internal pure returns (address, RecoverError) {
// EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
// unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
// the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
// signatures from current libraries generate a unique signature with an s-value in the lower half order.
//
// If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
// with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
// vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
// these malleable signatures as well.
if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
return (address(0), RecoverError.InvalidSignatureS);
}
if (v != 27 && v != 28) {
return (address(0), RecoverError.InvalidSignatureV);
}
// If the signature is valid (and not malleable), return the signer address
address signer = ecrecover(hash, v, r, s);
if (signer == address(0)) {
return (address(0), RecoverError.InvalidSignature);
}
return (signer, RecoverError.NoError);
}
/**
* @dev Overload of {ECDSA-recover} that receives the `v`,
* `r` and `s` signature fields separately.
*/
function recover(
bytes32 hash,
uint8 v,
bytes32 r,
bytes32 s
) internal pure returns (address) {
(address recovered, RecoverError error) = tryRecover(hash, v, r, s);
_throwError(error);
return recovered;
}
/**
* @dev Returns an Ethereum Signed Message, created from a `hash`. This
* produces hash corresponding to the one signed with the
* https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
* JSON-RPC method as part of EIP-191.
*
* See {recover}.
*/
function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
// 32 is the length in bytes of hash,
// enforced by the type signature above
return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
}
/**
* @dev Returns an Ethereum Signed Message, created from `s`. This
* produces hash corresponding to the one signed with the
* https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
* JSON-RPC method as part of EIP-191.
*
* See {recover}.
*/
function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n", Strings.toString(s.length), s));
}
/**
* @dev Returns an Ethereum Signed Typed Data, created from a
* `domainSeparator` and a `structHash`. This produces hash corresponding
* to the one signed with the
* https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
* JSON-RPC method as part of EIP-712.
*
* See {recover}.
*/
function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
return keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
}
}
// File: @openzeppelin/contracts/utils/Context.sol
// 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;
}
}
// File: @openzeppelin/contracts/access/Ownable.sol
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
/**
* @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 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 {
_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);
}
}
// File: @openzeppelin/contracts/token/ERC20/IERC20.sol
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
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);
}
// File: contracts/IAwooToken.sol
pragma solidity 0.8.12;
interface IAwooToken is IERC20 {
function increaseVirtualBalance(address account, uint256 amount) external;
function mint(address account, uint256 amount) external;
function balanceOfVirtual(address account) external view returns(uint256);
function spendVirtualAwoo(bytes32 hash, bytes memory sig, string calldata nonce, address account, uint256 amount) external;
}
// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
pragma solidity ^0.8.0;
/**
* @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);
}
// File: @openzeppelin/contracts/token/ERC20/ERC20.sol
// OpenZeppelin Contracts v4.4.1 (token/ERC20/ERC20.sol)
pragma solidity ^0.8.0;
/**
* @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 {}
}
// File: contracts/AwooToken.sol
pragma solidity 0.8.12;
contract AwooToken is IAwooToken, ERC20, ReentrancyGuard, Ownable, AddressChecksumStringUtil {
using ECDSA for bytes32;
using Strings for uint256;
/// @dev Controls whether or not the deposit/withdraw functionality is enabled
bool public isActive = true;
/// @dev The percentage of spent virtual AWOO taken as a fee
uint256 public awooFeePercentage = 10;
/// @dev The Awoo Studios account where fees are sent
address public awooStudiosAccount;
address[2] private _admins;
bool private _adminsSet;
/// @dev Keeps track of which contracts are explicitly allowed to add virtual AWOO to a holder's address, spend from it, or
/// in the future, mint ERC-20 tokens
mapping(address => bool) private _authorizedContracts;
/// @dev Keeps track of each holders virtual AWOO balance
mapping(address => uint256) private _virtualBalance;
/// @dev Keeps track of nonces used for spending events to prevent double spends
mapping(string => bool) private _usedNonces;
event AuthorizedContractAdded(address contractAddress, address addedBy);
event AuthorizedContractRemoved(address contractAddress, address removedBy);
event VirtualAwooSpent(address spender, uint256 amount);
constructor(address awooAccount) ERC20("Awoo Token", "AWOO") {
require(awooAccount != address(0), "Invalid awooAccount");
awooStudiosAccount = awooAccount;
}
/// @notice Allows an authorized contract to mint $AWOO
/// @param account The account to receive the minted $AWOO tokens
/// @param amount The amount of $AWOO to mint
function mint(address account, uint256 amount) external nonReentrant onlyAuthorizedContract {
require(account != address(0), "Cannot mint to the zero address");
require(amount > 0, "Amount cannot be zero");
_mint(account, amount);
}
/// @notice Allows the owner or an admin to add authorized contracts
/// @param contractAddress The address of the contract to authorize
function addAuthorizedContract(address contractAddress) external onlyOwnerOrAdmin {
require(isContract(contractAddress), "Not a contract address");
_authorizedContracts[contractAddress] = true;
emit AuthorizedContractAdded(contractAddress, _msgSender());
}
/// @notice Allows the owner or an admin to remove authorized contracts
/// @param contractAddress The address of the contract to revoke authorization for
function removeAuthorizedContract(address contractAddress) external onlyOwnerOrAdmin {
_authorizedContracts[contractAddress] = false;
emit AuthorizedContractRemoved(contractAddress, _msgSender());
}
/// @notice Exchanges virtual AWOO for ERC-20 $AWOO
/// @param amount The amount of virtual AWOO to withdraw
function withdraw(uint256 amount) external whenActive hasBalance(amount, _virtualBalance[_msgSender()]) nonReentrant {
_mint(_msgSender(), amount);
_virtualBalance[_msgSender()] -= amount;
}
/// @notice Exchanges ERC-20 $AWOO for virtual AWOO to be used in the Awoo Studios ecosystem
/// @param amount The amount of $AWOO to deposit
function deposit(uint256 amount) external whenActive hasBalance(amount, balanceOf(_msgSender())) nonReentrant {
_burn(_msgSender(), amount);
_virtualBalance[_msgSender()] += amount;
}
/// @notice Returns the amount of virtual AWOO held by the specified address
/// @param account The holder account to check
function balanceOfVirtual(address account) external view returns(uint256) {
return _virtualBalance[account];
}
/// @notice Returns the amount of ERC-20 $AWOO held by the specified address
/// @param account The holder account to check
function totalBalanceOf(address account) external view returns(uint256) {
return _virtualBalance[account] + balanceOf(account);
}
/// @notice Allows authorized contracts to increase a holders virtual AWOO
/// @param account The account to increase
/// @param amount The amount of virtual AWOO to increase the account by
function increaseVirtualBalance(address account, uint256 amount) external onlyAuthorizedContract {
_virtualBalance[account] += amount;
}
/// @notice Allows authorized contracts to faciliate the spending of virtual AWOO, and fees to be paid to
/// Awoo Studios.
/// @notice Only amounts that have been signed and verified by the token holder can be spent
/// @param hash The hash of the message displayed to and signed by the holder
/// @param sig The signature of the messages that was signed by the holder
/// @param nonce The unique code used to prevent double spends
/// @param account The account of the holder to debit
/// @param amount The amount of virtual AWOO to debit
function spendVirtualAwoo(bytes32 hash, bytes memory sig, string calldata nonce, address account, uint256 amount)
external onlyAuthorizedContract hasBalance(amount, _virtualBalance[account]) nonReentrant {
require(_usedNonces[nonce] == false, "Duplicate nonce");
require(matchAddresSigner(account, hash, sig), "Message signer mismatch"); // Make sure that the spend request was authorized (signed) by the holder
require(hashTransaction(account, amount) == hash, "Hash check failed"); // Make sure that only the amount authorized by the holder can be spent
// debit the holder's virtual AWOO account
_virtualBalance[account]-=amount;
// Mint the spending fee to the Awoo Studios account
_mint(awooStudiosAccount, ((amount * awooFeePercentage)/100));
_usedNonces[nonce] = true;
emit VirtualAwooSpent(account, amount);
}
/// @notice Allows the owner to specify two addresses allowed to administer this contract
/// @param adminAddresses A 2 item array of addresses
function setAdmins(address[2] calldata adminAddresses) external onlyOwner {
require(adminAddresses[0] != address(0) && adminAddresses[1] != address(0), "Invalid admin address");
_admins = adminAddresses;
_adminsSet = true;
}
/// @notice Allows the owner or an admin to activate/deactivate deposit and withdraw functionality
/// @notice This will only be used to disable functionality as a worst case scenario
/// @param active The value specifiying whether or not deposits/withdraws should be allowed
function setActiveState(bool active) external onlyOwnerOrAdmin {
isActive = active;
}
/// @notice Allows the owner to change the account used for collecting spending fees
/// @param awooAccount The new account
function setAwooStudiosAccount(address awooAccount) external onlyOwner {
require(awooAccount != address(0), "Invalid awooAccount");
awooStudiosAccount = awooAccount;
}
/// @notice Allows the owner to change the spending fee percentage
/// @param feePercentage The new fee percentage
function setFeePercentage(uint256 feePercentage) external onlyOwner {
awooFeePercentage = feePercentage; // We're intentionally allowing the fee percentage to be set to 0%, incase no fees need to be collected
}
/// @notice Allows the owner to withdraw any Ethereum that was accidentally sent to this contract
function rescueEth() external onlyOwner {
payable(owner()).transfer(address(this).balance);
}
/// @dev Derived from @openzeppelin/contracts/utils/Address.sol
function isContract(address account) private 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;
assembly {
size := extcodesize(account)
}
return size > 0;
}
/// @dev Validates the specified account against the account that signed the message
function matchAddresSigner(address account, bytes32 hash, bytes memory signature) private pure returns (bool) {
return account == hash.recover(signature);
}
/// @dev Hashes the message we expected the spender to sign so we can compare the hashes to ensure that the owner
/// of the specified address signed the same message
/// @dev fractional ether unit amounts aren't supported
function hashTransaction(address sender, uint256 amount) private pure returns (bytes32) {
require(amount == ((amount/1e18)*1e18), "Invalid amount");
// Virtual $AWOO, much like the ERC-20 $AWOO is stored with 18 implied decimal places.
// For user-friendliness, when prompting the user to sign the message, the amount is
// _displayed_ without the implied decimals, but it is charged with the implied decimals,
// so when validating the hash, we have to use the same value we displayed to the user.
// This only affects the display value, nothing else
amount = amount/1e18;
string memory message = string(abi.encodePacked(
"As the owner of Ethereum address\r\n",
toChecksumString(sender),
"\r\nI authorize the spending of ",
amount.toString()," virtual $AWOO"
));
uint256 messageLength = bytes(message).length;
bytes32 hash = keccak256(
abi.encodePacked(
"\x19Ethereum Signed Message:\n",messageLength.toString(),
message
)
);
return hash;
}
modifier onlyAuthorizedContract() {
require(_authorizedContracts[_msgSender()], "Sender is not authorized");
_;
}
modifier whenActive() {
require(isActive, "Contract is not active");
_;
}
modifier hasBalance(uint256 amount, uint256 balance) {
require(amount > 0, "Amount cannot be zero");
require(balance >= amount, "Insufficient Balance");
_;
}
modifier onlyOwnerOrAdmin() {
require(
_msgSender() == owner() ||
(_adminsSet &&
(_msgSender() == _admins[0] || _msgSender() == _admins[1])),
"Caller is not the owner or an admin"
);
_;
}
}
{
"compilationTarget": {
"AwooToken.sol": "AwooToken"
},
"evmVersion": "london",
"libraries": {},
"metadata": {
"bytecodeHash": "ipfs"
},
"optimizer": {
"enabled": true,
"runs": 1500
},
"remappings": []
}
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