Contract Diff Checker

Contract Name:
UpgradeBeaconProxy

Contract Source Code:

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @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
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 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");

        (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 functionCallWithValue(target, data, 0, "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");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // 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
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity 0.8.17;

// ============ 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));
  }
}

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