31 lines
896 B
Solidity
31 lines
896 B
Solidity
// SPDX-License-Identifier: MIT
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pragma solidity ^0.8.19;
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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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mapping(address => uint256) private _nonces;
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/**
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* @dev Returns an address nonce.
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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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