Files
openzeppelin-contracts/contracts/utils/Nonces.sol
Ernesto García b425a72240 Replace revert strings with custom errors (#4261)
Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>
Co-authored-by: Francisco <fg@frang.io>
2023-06-12 23:41:52 +00:00

47 lines
1.4 KiB
Solidity

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;
/**
* @dev Provides tracking nonces for addresses. Nonces will only increment.
*/
abstract contract Nonces {
/**
* @dev The nonce used for an `account` is not the expected current nonce.
*/
error InvalidAccountNonce(address account, uint256 currentNonce);
mapping(address => uint256) private _nonces;
/**
* @dev Returns an address nonce.
*/
function nonces(address owner) public view virtual returns (uint256) {
return _nonces[owner];
}
/**
* @dev Consumes a nonce.
*
* Returns the current value and increments nonce.
*/
function _useNonce(address owner) internal virtual returns (uint256) {
// For each account, the nonce has an initial value of 0, can only be incremented by one, and cannot be
// decremented or reset. This guarantees that the nonce never overflows.
unchecked {
// It is important to do x++ and not ++x here.
return _nonces[owner]++;
}
}
/**
* @dev Same as {_useNonce} but checking that `nonce` is the next valid for `owner`.
*/
function _useCheckedNonce(address owner, uint256 nonce) internal virtual returns (uint256) {
uint256 current = _useNonce(owner);
if (nonce != current) {
revert InvalidAccountNonce(owner, current);
}
return current;
}
}