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ReentrancyGuardUpgradeable.sol
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ReentrancyGuardUpgradeable.sol
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// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../LBErrors.sol";
/// @title Reentrancy Guard
/// @author Trader Joe
/// @notice Contract module that helps prevent reentrant calls to a function
abstract contract ReentrancyGuardUpgradeable {
// 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;
function __ReentrancyGuard_init() internal {
__ReentrancyGuard_init_unchained();
}
function __ReentrancyGuard_init_unchained() internal {
if (_status != 0) revert ReentrancyGuardUpgradeable__AlreadyInitialized();
_status = _NOT_ENTERED;
}
/// @notice 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
if (_status != _NOT_ENTERED) revert ReentrancyGuardUpgradeable__ReentrantCall();
// 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;
}
}