Contract Source Code:
pragma solidity 0.5.16;
import "./interface/IUpgradeSource.sol";
import "@openzeppelin/upgrades/contracts/upgradeability/BaseUpgradeabilityProxy.sol";
contract VaultProxy is BaseUpgradeabilityProxy {
constructor(address _implementation) public {
_setImplementation(_implementation);
}
/**
* The main logic. If the timer has elapsed and there is a schedule upgrade,
* the governance can upgrade the vault
*/
function upgrade() external {
(bool should, address newImplementation) = IUpgradeSource(address(this)).shouldUpgrade();
require(should, "Upgrade not scheduled");
_upgradeTo(newImplementation);
// the finalization needs to be executed on itself to update the storage of this proxy
// it also needs to be invoked by the governance, not by address(this), so delegatecall is needed
(bool success, bytes memory result) = address(this).delegatecall(
abi.encodeWithSignature("finalizeUpgrade()")
);
require(success, "Issue when finalizing the upgrade");
}
function implementation() external view returns (address) {
return _implementation();
}
}
pragma solidity 0.5.16;
interface IUpgradeSource {
function shouldUpgrade() external view returns (bool, address);
function finalizeUpgrade() external;
}
pragma solidity ^0.5.0;
import './Proxy.sol';
import '../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 Address of the current implementation
*/
function _implementation() internal view returns (address impl) {
bytes32 slot = IMPLEMENTATION_SLOT;
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(OpenZeppelinUpgradesAddress.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
bytes32 slot = IMPLEMENTATION_SLOT;
assembly {
sstore(slot, newImplementation)
}
}
}
pragma solidity ^0.5.0;
/**
* @title Proxy
* @dev Implements delegation of calls to other contracts, with proper
* forwarding of return values and bubbling of failures.
* It defines a fallback function that delegates all calls to the address
* returned by the abstract _implementation() internal function.
*/
contract Proxy {
/**
* @dev Fallback function.
* Implemented entirely in `_fallback`.
*/
function () payable external {
_fallback();
}
/**
* @return The Address of the implementation.
*/
function _implementation() internal view returns (address);
/**
* @dev Delegates execution to an implementation contract.
* This is a low level function that doesn't return to its internal call site.
* It will return to the external caller whatever the implementation returns.
* @param implementation Address to delegate.
*/
function _delegate(address implementation) internal {
assembly {
// Copy msg.data. We take full control of memory in this inline assembly
// block because it will not return to Solidity code. We overwrite the
// Solidity scratch pad at memory position 0.
calldatacopy(0, 0, calldatasize)
// Call the implementation.
// out and outsize are 0 because we don't know the size yet.
let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)
// Copy the returned data.
returndatacopy(0, 0, returndatasize)
switch result
// delegatecall returns 0 on error.
case 0 { revert(0, returndatasize) }
default { return(0, returndatasize) }
}
}
/**
* @dev Function that is run as the first thing in the fallback function.
* Can be redefined in derived contracts to add functionality.
* Redefinitions must call super._willFallback().
*/
function _willFallback() internal {
}
/**
* @dev fallback implementation.
* Extracted to enable manual triggering.
*/
function _fallback() internal {
_willFallback();
_delegate(_implementation());
}
}
pragma solidity ^0.5.0;
/**
* Utility library of inline functions on addresses
*
* Source https://raw.githubusercontent.com/OpenZeppelin/openzeppelin-solidity/v2.1.3/contracts/utils/Address.sol
* This contract is copied here and renamed from the original to avoid clashes in the compiled artifacts
* when the user imports a zos-lib contract (that transitively causes this contract to be compiled and added to the
* build/artifacts folder) as well as the vanilla Address implementation from an openzeppelin version.
*/
library OpenZeppelinUpgradesAddress {
/**
* Returns whether the target address is a contract
* @dev This function will return false if invoked during the constructor of a contract,
* as the code is not actually created until after the constructor finishes.
* @param account address of the account to check
* @return whether the target address is a contract
*/
function isContract(address account) internal view returns (bool) {
uint256 size;
// XXX Currently there is no better way to check if there is a contract in an address
// than to check the size of the code at that address.
// See https://ethereum.stackexchange.com/a/14016/36603
// for more details about how this works.
// TODO Check this again before the Serenity release, because all addresses will be
// contracts then.
// solhint-disable-next-line no-inline-assembly
assembly { size := extcodesize(account) }
return size > 0;
}
}