contracts/src/proxy/Initializable.sol
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/Initializable.sol) <https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v4.9.0/contracts/proxy/utils/Initializable.sol>
pragma solidity 0.8.24;
/**
* @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 proxied contracts do not make use of 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.
*
* The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
* reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
* case an upgrade adds a module that needs to be initialized.
*
* For example:
*
* ```solidity
* contract MyToken is ERC20Upgradeable {
* function initialize() initializer public {
* __ERC20_init("MyToken", "MTK");
* }
* }
*
* contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
* function initializeV2() reinitializer(2) public {
* __ERC20Permit_init("MyToken");
* }
* }
* ```
*
* 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 the proxy 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.
*
* [CAUTION]
* ====
* Avoid leaving a contract uninitialized.
*
* An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
* contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
* the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
*
* ```
* /// @custom:oz-upgrades-unsafe-allow constructor
* constructor() {
* _disableInitializers();
* }
* ```
*/
abstract contract Initializable {
/**
* @dev Storage of the initializable contract.
*
* It's implemented on a custom ERC-7201 namespace to reduce the risk of storage collisions
* when using with upgradeable contracts.
*
* @custom:storage-location erc7201:openzeppelin.storage.Initializable
*/
struct InitializableStorage {
/**
* @dev Indicates that the contract has been initialized.
*/
uint64 _initialized;
/**
* @dev Indicates that the contract is in the process of being initialized.
*/
bool _initializing;
}
// keccak256(abi.encode(uint256(keccak256("openzeppelin.storage.Initializable")) - 1))
bytes32 private constant _INITIALIZABLE_STORAGE =
0xf0c57e16840df040f15088dc2f81fe391c3923bec73e23a9662efc9c229c6a0e;
/**
* @dev The contract is already initialized.
*/
error AlreadyInitialized();
/**
* @dev The contract is not initializing.
*/
error NotInitializing();
/**
* @dev Triggered when the contract has been initialized or reinitialized.
*/
event Initialized(uint64 version);
/**
* @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
* `onlyInitializing` functions can be used to initialize parent contracts.
*
* Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
* constructor.
*
* Emits an {Initialized} event.
*/
modifier initializer() {
// solhint-disable-next-line var-name-mixedcase
InitializableStorage storage $ = _getInitializableStorage();
bool isTopLevelCall = !$._initializing;
uint64 initialized = $._initialized;
if (!(isTopLevelCall && initialized < 1) && !(address(this).code.length == 0 && initialized == 1)) {
revert AlreadyInitialized();
}
$._initialized = 1;
if (isTopLevelCall) {
$._initializing = true;
}
_;
if (isTopLevelCall) {
$._initializing = false;
emit Initialized(1);
}
}
/**
* @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
* contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
* used to initialize parent contracts.
*
* A reinitializer may be used after the original initialization step. This is essential to configure modules that
* are added through upgrades and that require initialization.
*
* When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
* cannot be nested. If one is invoked in the context of another, execution will revert.
*
* Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
* a contract, executing them in the right order is up to the developer or operator.
*
* WARNING: setting the version to 255 will prevent any future reinitialization.
*
* Emits an {Initialized} event.
*/
modifier reinitializer(uint64 version) {
// solhint-disable-next-line var-name-mixedcase
InitializableStorage storage $ = _getInitializableStorage();
if ($._initializing || $._initialized >= version) {
revert AlreadyInitialized();
}
$._initialized = version;
$._initializing = true;
_;
$._initializing = false;
emit Initialized(version);
}
/**
* @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
* {initializer} and {reinitializer} modifiers, directly or indirectly.
*/
modifier onlyInitializing() {
_checkInitializing();
_;
}
/**
* @dev Reverts if the contract is not in an initializing state. See {onlyInitializing}.
*/
function _checkInitializing() internal view virtual {
if (!_isInitializing()) {
revert NotInitializing();
}
}
/**
* @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
* Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
* to any version. It is recommended to use this to lock implementation contracts that are designed to be called
* through proxies.
*
* Emits an {Initialized} event the first time it is successfully executed.
*/
function _disableInitializers() internal virtual {
// solhint-disable-next-line var-name-mixedcase
InitializableStorage storage $ = _getInitializableStorage();
if ($._initializing) {
revert AlreadyInitialized();
}
if ($._initialized != type(uint64).max) {
$._initialized = type(uint64).max;
emit Initialized(type(uint64).max);
}
}
/**
* @dev Returns the highest version that has been initialized. See {reinitializer}.
*/
function _getInitializedVersion() internal view returns (uint64) {
return _getInitializableStorage()._initialized;
}
/**
* @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
*/
function _isInitializing() internal view returns (bool) {
return _getInitializableStorage()._initializing;
}
/**
* @dev Returns a pointer to the storage namespace.
*/
// solhint-disable-next-line var-name-mixedcase
function _getInitializableStorage() private pure returns (InitializableStorage storage $) {
assembly {
$.slot := _INITIALIZABLE_STORAGE
}
}
}