Contract Name:
UpgradeBeaconProxy
Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.11;
// ============ External Imports ============
import {Address} from "@openzeppelin/contracts/utils/Address.sol";
/**
* @title UpgradeBeaconProxy
* @notice
* Proxy contract which delegates all logic, including initialization,
* to an implementation contract.
* The implementation contract is stored within an Upgrade Beacon contract;
* the implementation contract can be changed by performing an upgrade on the Upgrade Beacon contract.
* The Upgrade Beacon contract for this Proxy is immutably specified at deployment.
* @dev This implementation combines the gas savings of keeping the UpgradeBeacon address outside of contract storage
* found in 0age's implementation:
* https://github.com/dharma-eng/dharma-smart-wallet/blob/master/contracts/proxies/smart-wallet/UpgradeBeaconProxyV1.sol
* With the added safety checks that the UpgradeBeacon and implementation are contracts at time of deployment
* found in OpenZeppelin's implementation:
* https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/proxy/beacon/BeaconProxy.sol
*/
contract UpgradeBeaconProxy {
// ============ Immutables ============
// Upgrade Beacon address is immutable (therefore not kept in contract storage)
address private immutable upgradeBeacon;
// ============ Constructor ============
/**
* @notice Validate that the Upgrade Beacon is a contract, then set its
* address immutably within this contract.
* Validate that the implementation is also a contract,
* Then call the initialization function defined at the implementation.
* The deployment will revert and pass along the
* revert reason if the initialization function reverts.
* @param _upgradeBeacon Address of the Upgrade Beacon to be stored immutably in the contract
* @param _initializationCalldata Calldata supplied when calling the initialization function
*/
constructor(address _upgradeBeacon, bytes memory _initializationCalldata)
payable
{
// Validate the Upgrade Beacon is a contract
require(Address.isContract(_upgradeBeacon), "beacon !contract");
// set the Upgrade Beacon
upgradeBeacon = _upgradeBeacon;
// Validate the implementation is a contract
address _implementation = _getImplementation(_upgradeBeacon);
require(
Address.isContract(_implementation),
"beacon implementation !contract"
);
// Call the initialization function on the implementation
if (_initializationCalldata.length > 0) {
_initialize(_implementation, _initializationCalldata);
}
}
// ============ External Functions ============
/**
* @notice Forwards all calls with data to _fallback()
* No public functions are declared on the contract, so all calls hit fallback
*/
fallback() external payable {
_fallback();
}
/**
* @notice Forwards all calls with no data to _fallback()
*/
receive() external payable {
_fallback();
}
// ============ Private Functions ============
/**
* @notice Call the initialization function on the implementation
* Used at deployment to initialize the proxy
* based on the logic for initialization defined at the implementation
* @param _implementation - Contract to which the initalization is delegated
* @param _initializationCalldata - Calldata supplied when calling the initialization function
*/
function _initialize(
address _implementation,
bytes memory _initializationCalldata
) private {
// Delegatecall into the implementation, supplying initialization calldata.
(bool _ok, ) = _implementation.delegatecall(_initializationCalldata);
// Revert and include revert data if delegatecall to implementation reverts.
if (!_ok) {
assembly {
returndatacopy(0, 0, returndatasize())
revert(0, returndatasize())
}
}
}
/**
* @notice Delegates function calls to the implementation contract returned by the Upgrade Beacon
*/
function _fallback() private {
_delegate(_getImplementation());
}
/**
* @notice Delegate function execution to the implementation contract
* @dev This is a low level function that doesn't return to its internal
* call site. It will return whatever is returned by the implementation to the
* external caller, reverting and returning the revert data if implementation
* reverts.
* @param _implementation - Address to which the function execution is delegated
*/
function _delegate(address _implementation) private {
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())
// Delegatecall to the implementation, supplying calldata and gas.
// Out and outsize are set to zero - instead, use the return buffer.
let result := delegatecall(
gas(),
_implementation,
0,
calldatasize(),
0,
0
)
// Copy the returned data from the return buffer.
returndatacopy(0, 0, returndatasize())
switch result
// Delegatecall returns 0 on error.
case 0 {
revert(0, returndatasize())
}
default {
return(0, returndatasize())
}
}
}
/**
* @notice Call the Upgrade Beacon to get the current implementation contract address
* @return _implementation Address of the current implementation.
*/
function _getImplementation()
private
view
returns (address _implementation)
{
_implementation = _getImplementation(upgradeBeacon);
}
/**
* @notice Call the Upgrade Beacon to get the current implementation contract address
* @dev _upgradeBeacon is passed as a parameter so that
* we can also use this function in the constructor,
* where we can't access immutable variables.
* @param _upgradeBeacon Address of the UpgradeBeacon storing the current implementation
* @return _implementation Address of the current implementation.
*/
function _getImplementation(address _upgradeBeacon)
private
view
returns (address _implementation)
{
// Get the current implementation address from the upgrade beacon.
(bool _ok, bytes memory _returnData) = _upgradeBeacon.staticcall("");
// Revert and pass along revert message if call to upgrade beacon reverts.
require(_ok, string(_returnData));
// Set the implementation to the address returned from the upgrade beacon.
_implementation = abi.decode(_returnData, (address));
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.2 <0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
// solhint-disable-next-line no-inline-assembly
assembly { size := extcodesize(account) }
return size > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.delegatecall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}