Files
core/contracts/upgradeability/VersionedInitializable.sol
Peter Michael dd137b2dee Initial commit
2022-01-25 15:19:42 -05:00

52 lines
1.9 KiB
Solidity

// SPDX-License-Identifier: agpl-3.0
pragma solidity 0.8.10;
import {Errors} from '../libraries/Errors.sol';
/**
* @title VersionedInitializable
*
* @dev Helper contract to implement initializer functions. To use it, replace
* the constructor with a function that has the `initializer` modifier.
* WARNING: Unlike constructors, initializer functions must be manually
* invoked. This applies both to deploying an Initializable contract, as well
* as extending an Initializable contract via inheritance.
* WARNING: When used with inheritance, manual care must be taken to not invoke
* a parent initializer twice, or ensure that all initializers are idempotent,
* because this is not dealt with automatically as with constructors.
*
* This is slightly modified from [Aave's version.](https://github.com/aave/protocol-v2/blob/6a503eb0a897124d8b9d126c915ffdf3e88343a9/contracts/protocol/libraries/aave-upgradeability/VersionedInitializable.sol)
*
* @author Lens, inspired by Aave's implementation, which is in turn inspired by OpenZeppelin's
* Initializable contract
*/
abstract contract VersionedInitializable {
address private immutable originalImpl;
/**
* @dev Indicates that the contract has been initialized.
*/
uint256 private lastInitializedRevision = 0;
/**
* @dev Modifier to use in the initializer function of a contract.
*/
modifier initializer() {
uint256 revision = getRevision();
if (address(this) == originalImpl) revert Errors.CannotInitImplementation();
if (revision <= lastInitializedRevision) revert Errors.Initialized();
lastInitializedRevision = revision;
_;
}
constructor() {
originalImpl = address(this);
}
/**
* @dev returns the revision number of the contract
* Needs to be defined in the inherited class as a constant.
**/
function getRevision() internal pure virtual returns (uint256);
}