You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
48 lines
1.7 KiB
48 lines
1.7 KiB
// SPDX-License-Identifier: MIT
|
|
|
|
// solhint-disable-next-line compiler-version
|
|
pragma solidity ^0.8.0;
|
|
|
|
/**
|
|
* @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
|
|
* behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
|
|
* external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
|
|
* function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
|
|
*
|
|
* TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
|
|
* possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
|
|
*
|
|
* CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
|
|
* that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
|
|
*/
|
|
abstract contract Initializable {
|
|
|
|
/**
|
|
* @dev Indicates that the contract has been initialized.
|
|
*/
|
|
bool private _initialized;
|
|
|
|
/**
|
|
* @dev Indicates that the contract is in the process of being initialized.
|
|
*/
|
|
bool private _initializing;
|
|
|
|
/**
|
|
* @dev Modifier to protect an initializer function from being invoked twice.
|
|
*/
|
|
modifier initializer() {
|
|
require(_initializing || !_initialized, "Initializable: contract is already initialized");
|
|
|
|
bool isTopLevelCall = !_initializing;
|
|
if (isTopLevelCall) {
|
|
_initializing = true;
|
|
_initialized = true;
|
|
}
|
|
|
|
_;
|
|
|
|
if (isTopLevelCall) {
|
|
_initializing = false;
|
|
}
|
|
}
|
|
}
|
|
|