aave-protocol-v2/contracts/libraries/openzeppelin-upgradeability/BaseUpgradeabilityProxy.sol

66 lines
2.0 KiB
Solidity

// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.6.8;
import "./Proxy.sol";
import "@openzeppelin/contracts/utils/Address.sol";
/**
* @title BaseUpgradeabilityProxy
* @dev This contract implements a proxy that allows to change the
* implementation address to which it will delegate.
* Such a change is called an implementation upgrade.
*/
contract BaseUpgradeabilityProxy is Proxy {
/**
* @dev Emitted when the implementation is upgraded.
* @param implementation Address of the new implementation.
*/
event Upgraded(address indexed implementation);
/**
* @dev Storage slot with the address of the current implementation.
* This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
* validated in the constructor.
*/
bytes32 internal constant IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
/**
* @dev Returns the current implementation.
* @return impl Address of the current implementation
*/
function _implementation() internal override view returns (address impl) {
bytes32 slot = IMPLEMENTATION_SLOT;
//solium-disable-next-line
assembly {
impl := sload(slot)
}
}
/**
* @dev Upgrades the proxy to a new implementation.
* @param newImplementation Address of the new implementation.
*/
function _upgradeTo(address newImplementation) internal {
_setImplementation(newImplementation);
emit Upgraded(newImplementation);
}
/**
* @dev Sets the implementation address of the proxy.
* @param newImplementation Address of the new implementation.
*/
function _setImplementation(address newImplementation) internal {
require(
Address.isContract(newImplementation),
"Cannot set a proxy implementation to a non-contract address"
);
bytes32 slot = IMPLEMENTATION_SLOT;
//solium-disable-next-line
assembly {
sstore(slot, newImplementation)
}
}
}