47 lines
1.5 KiB
Solidity
47 lines
1.5 KiB
Solidity
// SPDX-License-Identifier: MIT
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// OpenZeppelin Contracts (last updated v5.0.0) (utils/Nonces.sol)
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pragma solidity ^0.8.20;
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/**
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* @dev Provides tracking nonces for addresses. Nonces will only increment.
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*/
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abstract contract Nonces {
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/**
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* @dev The nonce used for an `account` is not the expected current nonce.
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*/
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error InvalidAccountNonce(address account, uint256 currentNonce);
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mapping(address account => uint256) private _nonces;
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/**
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* @dev Returns the next unused nonce for an address.
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*/
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function nonces(address owner) public view virtual returns (uint256) {
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return _nonces[owner];
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}
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/**
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* @dev Consumes a nonce.
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*
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* Returns the current value and increments nonce.
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*/
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function _useNonce(address owner) internal virtual returns (uint256) {
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// For each account, the nonce has an initial value of 0, can only be incremented by one, and cannot be
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// decremented or reset. This guarantees that the nonce never overflows.
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unchecked {
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// It is important to do x++ and not ++x here.
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return _nonces[owner]++;
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}
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}
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/**
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* @dev Same as {_useNonce} but checking that `nonce` is the next valid for `owner`.
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*/
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function _useCheckedNonce(address owner, uint256 nonce) internal virtual {
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uint256 current = _useNonce(owner);
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if (nonce != current) {
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revert InvalidAccountNonce(owner, current);
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}
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}
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}
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