Contract Source Code:
// there are 2 gameSessions played per session
// first 4 turns are placing 4x1 blocks flat
// next 24 turns are placing 2x1 blocks any rotation
// at this point game starts another game
// first 4 turns are placing 4x1 blocks flat
// next 24 turns are placing 2x1 blocks any rotation
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
contract Huego {
using SafeERC20 for IERC20;
uint8 constant GRID_SIZE = 8;
uint256 public timeLimit = 600; // 10 minutes per player
address public owner;
uint256 public feePercentage = 500; // 5%
modifier onlyOwner() {
require(msg.sender == owner, "Not the owner");
_;
}
event BlockPlaced(uint256 indexed sessionId, uint8 indexed game, uint8 turn, uint8 pieceType, uint8 x, uint8 z, uint8 y, Rotation rotation);
struct WagerInfo {
uint256 amount;
bool processed; // To prevent double-processing
}
struct WagerProposal {
uint256 sessionId;
uint256 amount;
}
struct GameSession {
address player1;
address player2;
WagerInfo wager;
uint8 turn;
uint8 game; // either 0 or 1
uint256 gameStartTime;
uint256 lastMoveTime;
uint256 timeRemainingP1;
uint256 timeRemainingP2;
bool gameEnded;
topStack[][] initialStacks; // basically [2][16]
}
struct topStack {
uint8 x;
uint8 z;
uint8 y;
uint8 color;
}
// wager proposals maps address and sessionId to the wager proposal
mapping(address => mapping(uint256 => WagerProposal)) public wagerProposals;
// lets map user to their gameSession
mapping(address => uint256) public userGameSession;
struct GameGrid {
topStack[8][8] grid;
}
// GameSession ID -> [game0, game1] -> 8x8 grid
mapping(uint256 => GameGrid[2]) private stacksGrid;
GameSession[] public gameSessions; // List of gameSessions
// Colors: 0 = empty, 1 = yellow, 2 = purple, 3 = orange, 4 = green
enum Rotation {X, Z, Y}
constructor() {
owner = msg.sender;
// lets create a dummy gameSession to start from 1
gameSessions.push();
}
function getInitialStacks(uint256 sessionId, uint8 game) external view returns (topStack[] memory) {
return gameSessions[sessionId].initialStacks[game];
}
function getStacksGrid(uint256 sessionId, uint8 game) external view returns (topStack[8][8] memory) {
return stacksGrid[sessionId][game].grid;
}
function proposeWager(uint256 sessionId, uint256 _amount) public payable {
_proposeWager(sessionId, _amount, msg.sender);
}
function acceptWagerProposal(uint256 sessionId, uint256 _amount) public payable {
_acceptWager(sessionId, _amount, msg.sender);
}
function acceptAndProposeWager(uint256 sessionId, uint256 _amount) external payable {
_acceptWager(sessionId, _amount, msg.sender);
_proposeWager(sessionId, _amount, msg.sender);
}
// Internal helper functions to reduce redundancy
function _proposeWager(uint256 sessionId, uint256 _amount, address sender) internal {
require(sender == gameSessions[sessionId].player1 || sender == gameSessions[sessionId].player2, "Not a player of this game");
require(msg.value == _amount, "Wager amount mismatch");
uint currentWagerAmount = wagerProposals[sender][sessionId].amount;
wagerProposals[sender][sessionId] = WagerProposal({
sessionId: sessionId,
amount: _amount
});
if (currentWagerAmount != 0) {
(bool success,) = payable(sender).call{value: currentWagerAmount}("");
require(success, "Refund failed");
}
}
function _acceptWager(uint256 sessionId, uint256 _amount, address sender) internal {
address proposer = (sender == gameSessions[sessionId].player1) ? gameSessions[sessionId].player2 : gameSessions[sessionId].player1;
require(wagerProposals[proposer][sessionId].amount != 0, "No wager proposal");
require(!gameSessions[sessionId].wager.processed, "Wager already processed");
require(msg.value == wagerProposals[proposer][sessionId].amount, "Wager amount mismatch");
require(_amount == wagerProposals[proposer][sessionId].amount, "Wager amount mismatch");
gameSessions[sessionId].wager.amount += wagerProposals[proposer][sessionId].amount;
delete wagerProposals[proposer][sessionId];
// Refund any previous proposal from the sender
if (wagerProposals[sender][sessionId].amount != 0) {
(bool success,) = payable(sender).call{value: wagerProposals[sender][sessionId].amount}("");
require(success, "Refund failed");
delete wagerProposals[sender][sessionId];
}
}
function cancelWagerProposal(uint256 sessionId) external {
require(wagerProposals[msg.sender][sessionId].amount != 0, "No wager proposal exists");
// refund the player
(bool success,) = payable(msg.sender).call{value: wagerProposals[msg.sender][sessionId].amount}("");
require(success, "Transfer failed");
delete wagerProposals[msg.sender][sessionId];
}
function placeInitial4x1Stack(uint256 sessionId, uint8 game, uint8 x, uint8 z, uint8 color) internal {
require(game < 2, "Invalid game index");
require(x + 1 < GRID_SIZE && z + 1 < GRID_SIZE, "Invalid coordinates");
require(stacksGrid[sessionId][game].grid[x][z].color == 0, "Grid has a stack");
require(stacksGrid[sessionId][game].grid[x + 1][z].color == 0, "Grid has a stack");
require(stacksGrid[sessionId][game].grid[x][z + 1].color == 0, "Grid has a stack");
require(stacksGrid[sessionId][game].grid[x + 1][z + 1].color == 0, "Grid has a stack");
topStack memory stack1 = topStack(x, z, 0, color);
topStack memory stack2 = topStack(x + 1, z, 0, color);
topStack memory stack3 = topStack(x, z + 1, 0, color);
topStack memory stack4 = topStack(x + 1, z + 1, 0, color);
// If it's not the first placement, check for a valid neighbor
if (gameSessions[sessionId].turn > 1) {
// Predefined offsets for the 8 unique neighboring positions
int8[8] memory dx = [ int8(-1), int8(-1), int8(0), int8(0), int8(2), int8(2), int8(0), int8(1)];
int8[8] memory dz = [ int8(0), int8(1), int8(2), int8(2), int8(0), int8(1), int8(-1), int8(-1)];
bool found = false;
for (uint8 i = 0; i < 8; i++) {
int8 nx = int8(x) + dx[i];
int8 nz = int8(z) + dz[i];
// Ensure within grid bounds before checking
if (nx >= 0 && nx < int8(GRID_SIZE) && nz >= 0 && nz < int8(GRID_SIZE)) {
if (stacksGrid[sessionId][game].grid[uint8(nx)][uint8(nz)].color != 0) {
found = true;
break;
}
}
}
require(found, "No adjacent stack");
}
stacksGrid[sessionId][game].grid[x][z] = stack1;
stacksGrid[sessionId][game].grid[x + 1][z] = stack2;
stacksGrid[sessionId][game].grid[x][z + 1] = stack3;
stacksGrid[sessionId][game].grid[x + 1][z + 1] = stack4;
// Calculate the correct index in initialStacks based on turn
// uint8 turnIndex = (gameSessions[sessionId].turn - 1) * 4; // Each turn places 4 blocks
gameSessions[sessionId].initialStacks[game].push(stack1);
gameSessions[sessionId].initialStacks[game].push(stack2);
gameSessions[sessionId].initialStacks[game].push(stack3);
gameSessions[sessionId].initialStacks[game].push(stack4);
emit BlockPlaced(sessionId, game, gameSessions[sessionId].turn, 1, x, z, 0, Rotation.X);
}
function createSession(address player1, address player2) external {
// only player 1 can create a session
require(msg.sender == player2, "Not player 2");
// player 1 and 2 must not have an active game
require(userGameSession[player1] == 0, "Player 1 has an active session");
require(userGameSession[player2] == 0, "Player 2 has an active game");
uint256 sessionId = gameSessions.length;
GameSession storage session = gameSessions.push();
session.player1 = player1;
session.player2 = player2;
session.wager = WagerInfo(0, false);
session.game = 0;
session.gameStartTime = block.timestamp;
session.lastMoveTime = block.timestamp;
session.timeRemainingP1 = timeLimit;
session.timeRemainingP2 = timeLimit;
session.gameEnded = false;
// **Fix:** Initialize `initialStacks` before adding elements
session.initialStacks.push(); // First game session
session.initialStacks.push(); // Second game session
userGameSession[player1] = sessionId;
userGameSession[player2] = sessionId;
session.turn = 1;
}
function play(uint256 sessionId, uint8 x, uint8 z, Rotation rotation) external {
GameSession storage session = gameSessions[sessionId];
// game must not have ended
require(!session.gameEnded, "GameSession has ended");
// only player on turn can play
address starter = session.game == 0 ? session.player1 : session.player2;
address nonStarter = session.game == 0 ? session.player2 : session.player1;
address onTurn = session.turn % 2 == 1 ? starter : nonStarter;
require(msg.sender == onTurn, "Not your turn");
uint8 currentColor = ((session.turn - 1) % 4) + 1;
// requirement that the player still has time
if (onTurn == session.player1) {
require(block.timestamp - session.lastMoveTime < session.timeRemainingP1, "Player 1 ran out of time");
session.timeRemainingP1 -= block.timestamp - session.lastMoveTime;
} else {
require(block.timestamp - session.lastMoveTime < session.timeRemainingP2, "Player 2 ran out of time");
session.timeRemainingP2 -= block.timestamp - session.lastMoveTime;
}
// we are placing initial stacks
if(session.turn <= 4) {
placeInitial4x1Stack(sessionId, session.game, x, z, currentColor);
} else {
placeBlock(sessionId, session.game, x, z, currentColor);
if (rotation == Rotation.X) {
require(checkStackWithColorExists(sessionId, session.game, currentColor), "No stack with color exists");
placeBlock(sessionId, session.game, x + 1, z, currentColor);
} else if (rotation == Rotation.Z) {
require(checkStackWithColorExists(sessionId, session.game, currentColor), "No stack with color exists");
placeBlock(sessionId, session.game, x, z + 1, currentColor);
} else {
placeBlock(sessionId, session.game, x, z, currentColor);
}
// game ends on turn 28
if (session.turn == 28) {
if(session.game == 0) {
session.game = 1;
session.turn = 0;
} else {
session.gameEnded = true;
}
}
emit BlockPlaced(sessionId, session.game, session.turn, 2, x, z, stacksGrid[sessionId][session.game].grid[x][z].y, rotation);
}
session.lastMoveTime = block.timestamp;
session.turn += 1;
}
function checkStackWithColorExists(uint256 sessionId, uint8 game, uint8 color) internal view returns (bool) {
for (uint8 i = 0; i < 16; i++) {
if (stacksGrid[sessionId][game].grid[gameSessions[sessionId].initialStacks[game][i].x][gameSessions[sessionId].initialStacks[game][i].z].color == color) {
return true;
}
}
return false;
}
function placeBlock(uint256 sessionId, uint8 game, uint8 x, uint8 z, uint8 currentColor) internal {
require(stacksGrid[sessionId][game].grid[x][z].color != 0, "Stack does not exist");
stacksGrid[sessionId][game].grid[x][z].y += 1;
stacksGrid[sessionId][game].grid[x][z].color = currentColor;
}
// SCORING
// • Base Points: 1 point for each cube on top of any stack
// • Bonus Points: +1 point for cubes on the highest and lowest VISIBLE stacks
// • GameSession ends when all cubes are placed or when a player runs out of time
function calculateGamePoints(uint256 sessionId, uint8 game) public view returns (uint256, uint256) {
uint256 starterPoints = 0;
uint256 nonStarterPoints = 0;
uint8 highestStack = 0;
// first lets loop to find the highest stack
for (uint8 i = 0; i < 16; i++) {
uint x = gameSessions[sessionId].initialStacks[game][i].x;
uint z = gameSessions[sessionId].initialStacks[game][i].z;
topStack memory stack = stacksGrid[sessionId][game].grid[x][z];
if (stack.y > highestStack) {
highestStack = stack.y;
}
}
uint lowestStack = highestStack;
// now lets loop to find the lowest stack
for (uint8 i = 0; i < 16; i++) {
uint x = gameSessions[sessionId].initialStacks[game][i].x;
uint z = gameSessions[sessionId].initialStacks[game][i].z;
topStack memory stack = stacksGrid[sessionId][game].grid[x][z];
if (stack.y < lowestStack) {
lowestStack = stack.y;
}
}
for (uint8 i = 0; i < 16; i++) {
uint x = gameSessions[sessionId].initialStacks[game][i].x;
uint z = gameSessions[sessionId].initialStacks[game][i].z;
topStack memory stack = stacksGrid[sessionId][game].grid[x][z];
if (stack.y == highestStack || stack.y == lowestStack) {
// color 1 and color 3 belong to player 1
if (stack.color == 1 || stack.color == 3) {
starterPoints += 2;
} else {
nonStarterPoints += 2;
}
} else {
if (stack.color == 1 || stack.color == 3) {
starterPoints += 1;
} else {
nonStarterPoints += 1;
}
}
}
return (starterPoints, nonStarterPoints);
}
// receive reward
function acceptRewards(uint256 sessionId) external {
GameSession storage session = gameSessions[sessionId];
require(!session.wager.processed, "Wager already processed");
session.wager.processed = true;
address winner;
if(session.game == 1 && session.turn == 29 && session.gameEnded) {
uint256 totalPlayer1Points = 0;
uint256 totalPlayer2Points = 0;
(uint256 starterPoints0, uint256 nonStarterPoints0) = calculateGamePoints(sessionId, 0);
(uint256 starterPoints1, uint256 nonStarterPoints1) = calculateGamePoints(sessionId, 1);
totalPlayer1Points += starterPoints0;
totalPlayer2Points += nonStarterPoints0;
totalPlayer1Points += nonStarterPoints1;
totalPlayer2Points += starterPoints1;
if (totalPlayer1Points > totalPlayer2Points) {
winner = session.player1;
} else if (totalPlayer2Points > totalPlayer1Points) {
winner = session.player2;
} else {
// require either player1, player2
require(msg.sender == session.player1 || msg.sender == session.player2, "Not a player of this game");
// Tie case, refund wager to both players
uint256 feeEach = session.wager.amount * feePercentage / 10000;
uint256 rewardSplit = session.wager.amount - feeEach;
(bool success1,) = payable(session.player1).call{value: rewardSplit}("");
require(success1, "Transfer failed");
(bool success2,) = payable(session.player2).call{value: rewardSplit}("");
require(success2, "Transfer failed");
(bool success3,) = payable(owner).call{value: 2 * feeEach}("");
require(success3, "Transfer failed");
return;
}
} else {
// lets throw require current turn is 29
address starter = session.game == 0 ? session.player1 : session.player2;
address nonStarter = session.game == 0 ? session.player2 : session.player1;
address onTurn = session.turn % 2 == 1 ? starter : nonStarter;
// if not turn 28, game has not ended, we can calculate the winner one player runs out of time
if (onTurn == session.player1) {
require(block.timestamp - session.lastMoveTime > session.timeRemainingP1, "Player 1 still has time");
winner = session.player2;
} else {
require(block.timestamp - session.lastMoveTime > session.timeRemainingP2, "Player 2 still has time");
winner = session.player1;
}
}
// caller has to be the winner
require(msg.sender == winner, "Not the winner");
uint256 pot = session.wager.amount * 2;
uint256 fee = pot * feePercentage / 10000;
uint256 reward = pot - fee;
(bool success4,) = payable(winner).call{value: reward}("");
require(success4, "Transfer failed");
(bool success5,) = payable(owner).call{value: fee}("");
require(success5, "Transfer failed");
}
function setFeePercentage(uint256 _feePercentage) external onlyOwner {
require(_feePercentage <= 1000, "Fee too high"); // Max 10%
feePercentage = _feePercentage;
}
function setGameTimeLimit(uint256 _timeLimit) external onlyOwner {
timeLimit = _timeLimit;
}
function withdrawERC20(IERC20 erc20Token) external onlyOwner {
uint256 erc20Balance = erc20Token.balanceOf(address(this));
erc20Token.safeTransfer(msg.sender, erc20Balance);
}
// if funds are stuck on contract for some reason
function withdraw(uint256 amount) external onlyOwner {
(bool success,) = payable(msg.sender).call{value: amount}("");
require(success, "Transfer failed");
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.20;
/**
* @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 value of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the value of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves a `value` amount of 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 value) 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 a `value` amount of tokens 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 value) external returns (bool);
/**
* @dev Moves a `value` amount of tokens from `from` to `to` using the
* allowance mechanism. `value` 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 value) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.20;
import {IERC20} from "../IERC20.sol";
import {IERC20Permit} from "../extensions/IERC20Permit.sol";
import {Address} from "../../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using Address for address;
/**
* @dev An operation with an ERC20 token failed.
*/
error SafeERC20FailedOperation(address token);
/**
* @dev Indicates a failed `decreaseAllowance` request.
*/
error SafeERC20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);
/**
* @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
* non-reverting calls are assumed to be successful.
*/
function safeTransfer(IERC20 token, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeCall(token.transfer, (to, value)));
}
/**
* @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
* calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
*/
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeCall(token.transferFrom, (from, to, value)));
}
/**
* @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
* non-reverting calls are assumed to be successful.
*/
function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 oldAllowance = token.allowance(address(this), spender);
forceApprove(token, spender, oldAllowance + value);
}
/**
* @dev Decrease the calling contract's allowance toward `spender` by `requestedDecrease`. If `token` returns no
* value, non-reverting calls are assumed to be successful.
*/
function safeDecreaseAllowance(IERC20 token, address spender, uint256 requestedDecrease) internal {
unchecked {
uint256 currentAllowance = token.allowance(address(this), spender);
if (currentAllowance < requestedDecrease) {
revert SafeERC20FailedDecreaseAllowance(spender, currentAllowance, requestedDecrease);
}
forceApprove(token, spender, currentAllowance - requestedDecrease);
}
}
/**
* @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
* non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
* to be set to zero before setting it to a non-zero value, such as USDT.
*/
function forceApprove(IERC20 token, address spender, uint256 value) internal {
bytes memory approvalCall = abi.encodeCall(token.approve, (spender, value));
if (!_callOptionalReturnBool(token, approvalCall)) {
_callOptionalReturn(token, abi.encodeCall(token.approve, (spender, 0)));
_callOptionalReturn(token, approvalCall);
}
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data);
if (returndata.length != 0 && !abi.decode(returndata, (bool))) {
revert SafeERC20FailedOperation(address(token));
}
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*
* This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
*/
function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
// and not revert is the subcall reverts.
(bool success, bytes memory returndata) = address(token).call(data);
return success && (returndata.length == 0 || abi.decode(returndata, (bool))) && address(token).code.length > 0;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/extensions/IERC20Permit.sol)
pragma solidity ^0.8.20;
/**
* @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
* https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
*
* Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
* presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
* need to send a transaction, and thus is not required to hold Ether at all.
*
* ==== Security Considerations
*
* There are two important considerations concerning the use of `permit`. The first is that a valid permit signature
* expresses an allowance, and it should not be assumed to convey additional meaning. In particular, it should not be
* considered as an intention to spend the allowance in any specific way. The second is that because permits have
* built-in replay protection and can be submitted by anyone, they can be frontrun. A protocol that uses permits should
* take this into consideration and allow a `permit` call to fail. Combining these two aspects, a pattern that may be
* generally recommended is:
*
* ```solidity
* function doThingWithPermit(..., uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
* try token.permit(msg.sender, address(this), value, deadline, v, r, s) {} catch {}
* doThing(..., value);
* }
*
* function doThing(..., uint256 value) public {
* token.safeTransferFrom(msg.sender, address(this), value);
* ...
* }
* ```
*
* Observe that: 1) `msg.sender` is used as the owner, leaving no ambiguity as to the signer intent, and 2) the use of
* `try/catch` allows the permit to fail and makes the code tolerant to frontrunning. (See also
* {SafeERC20-safeTransferFrom}).
*
* Additionally, note that smart contract wallets (such as Argent or Safe) are not able to produce permit signatures, so
* contracts should have entry points that don't rely on permit.
*/
interface IERC20Permit {
/**
* @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
* given ``owner``'s signed approval.
*
* IMPORTANT: The same issues {IERC20-approve} has related to transaction
* ordering also apply here.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `deadline` must be a timestamp in the future.
* - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
* over the EIP712-formatted function arguments.
* - the signature must use ``owner``'s current nonce (see {nonces}).
*
* For more information on the signature format, see the
* https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
* section].
*
* CAUTION: See Security Considerations above.
*/
function permit(
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) external;
/**
* @dev Returns the current nonce for `owner`. This value must be
* included whenever a signature is generated for {permit}.
*
* Every successful call to {permit} increases ``owner``'s nonce by one. This
* prevents a signature from being used multiple times.
*/
function nonces(address owner) external view returns (uint256);
/**
* @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
*/
// solhint-disable-next-line func-name-mixedcase
function DOMAIN_SEPARATOR() external view returns (bytes32);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Address.sol)
pragma solidity ^0.8.20;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev The ETH balance of the account is not enough to perform the operation.
*/
error AddressInsufficientBalance(address account);
/**
* @dev There's no code at `target` (it is not a contract).
*/
error AddressEmptyCode(address target);
/**
* @dev A call to an address target failed. The target may have reverted.
*/
error FailedInnerCall();
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://consensys.net/diligence/blog/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.8.20/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
if (address(this).balance < amount) {
revert AddressInsufficientBalance(address(this));
}
(bool success, ) = recipient.call{value: amount}("");
if (!success) {
revert FailedInnerCall();
}
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain `call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason or custom error, it is bubbled
* up by this function (like regular Solidity function calls). However, if
* the call reverted with no returned reason, this function reverts with a
* {FailedInnerCall} error.
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*/
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
if (address(this).balance < value) {
revert AddressInsufficientBalance(address(this));
}
(bool success, bytes memory returndata) = target.call{value: value}(data);
return verifyCallResultFromTarget(target, success, returndata);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResultFromTarget(target, success, returndata);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResultFromTarget(target, success, returndata);
}
/**
* @dev Tool to verify that a low level call to smart-contract was successful, and reverts if the target
* was not a contract or bubbling up the revert reason (falling back to {FailedInnerCall}) in case of an
* unsuccessful call.
*/
function verifyCallResultFromTarget(
address target,
bool success,
bytes memory returndata
) internal view returns (bytes memory) {
if (!success) {
_revert(returndata);
} else {
// only check if target is a contract if the call was successful and the return data is empty
// otherwise we already know that it was a contract
if (returndata.length == 0 && target.code.length == 0) {
revert AddressEmptyCode(target);
}
return returndata;
}
}
/**
* @dev Tool to verify that a low level call was successful, and reverts if it wasn't, either by bubbling the
* revert reason or with a default {FailedInnerCall} error.
*/
function verifyCallResult(bool success, bytes memory returndata) internal pure returns (bytes memory) {
if (!success) {
_revert(returndata);
} else {
return returndata;
}
}
/**
* @dev Reverts with returndata if present. Otherwise reverts with {FailedInnerCall}.
*/
function _revert(bytes memory returndata) private pure {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
/// @solidity memory-safe-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert FailedInnerCall();
}
}
}