Contract Source Code:
// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity 0.7.5;
import "@openzeppelin/contracts/utils/Address.sol";
import "../interfaces/IPoolEscrow.sol";
/**
* @title PoolEscrow
*
* @dev PoolEscrow contract is used to receive transfers from ETH2 system contract for the pool validators.
* The withdrawal credentials of the Pool must be set to
* https://github.com/ethereum/eth2.0-specs/blob/v1.1.0-alpha.2/specs/phase0/validator.md#eth1_address_withdrawal_prefix
* using the address of this contract as a destination.
*/
contract PoolEscrow is IPoolEscrow {
using Address for address payable;
// @dev The address of the current contract owner.
address public override owner;
// @dev The address the ownership is planned to be transferred to.
address public override futureOwner;
/**
* @dev Constructor for initializing the PoolEscrow contract.
* @param _owner - address of the contract owner.
*/
constructor(address _owner) {
owner = _owner;
emit OwnershipTransferApplied(address(0), _owner);
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner == msg.sender, "PoolEscrow: caller is not the owner");
_;
}
/**
* @dev See {IPoolEscrow-commitOwnershipTransfer}.
*/
function commitOwnershipTransfer(address newOwner) external override onlyOwner {
// can be zero address to reset incorrect future owner
futureOwner = newOwner;
emit OwnershipTransferCommitted(msg.sender, newOwner);
}
/**
* @dev See {IPoolEscrow-applyOwnershipTransfer}.
*/
function applyOwnershipTransfer() external override {
address newOwner = futureOwner;
require(newOwner == msg.sender, "PoolEscrow: caller is not the future owner");
emit OwnershipTransferApplied(owner, newOwner);
(owner, futureOwner) = (newOwner, address(0));
}
/**
* @dev See {IPoolEscrow-withdraw}.
*/
function withdraw(address payable payee, uint256 amount) external override onlyOwner {
require(payee != address(0), "PoolEscrow: payee is the zero address");
emit Withdrawn(msg.sender, payee, amount);
payee.sendValue(amount);
}
/**
* @dev Function for receiving withdrawals from ETH2 system contract.
*/
receive() external payable { }
}
// 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);
}
}
}
}
// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity 0.7.5;
/**
* @dev Interface of the PoolEscrow contract.
*/
interface IPoolEscrow {
/**
* @dev Event for tracking withdrawn ether.
* @param sender - the address of the transaction sender.
* @param payee - the address where the funds were transferred to.
* @param amount - the amount of ether transferred to payee.
*/
event Withdrawn(address indexed sender, address indexed payee, uint256 amount);
/**
* @dev Event for tracking ownership transfer commits.
* @param currentOwner - the address of the current owner.
* @param futureOwner - the address the ownership is planned to be transferred to.
*/
event OwnershipTransferCommitted(address indexed currentOwner, address indexed futureOwner);
/**
* @dev Event for tracking ownership transfers.
* @param previousOwner - the address the ownership was transferred from.
* @param newOwner - the address the ownership was transferred to.
*/
event OwnershipTransferApplied(address indexed previousOwner, address indexed newOwner);
/**
* @dev Function for retrieving the address of the current owner.
*/
function owner() external view returns (address);
/**
* @dev Function for retrieving the address of the future owner.
*/
function futureOwner() external view returns (address);
/**
* @dev Commit contract ownership transfer to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function commitOwnershipTransfer(address newOwner) external;
/**
* @dev Apply contract ownership transfer to a new account (`futureOwner`).
* Can only be called by the future owner.
*/
function applyOwnershipTransfer() external;
/**
* @dev Withdraw balance for a payee, forwarding all gas to the
* recipient. Can only be called by the current owner.
*
* WARNING: Forwarding all gas opens the door to reentrancy vulnerabilities.
* Make sure you trust the recipient, or are either following the
* checks-effects-interactions pattern or using {ReentrancyGuard}.
*
* @param payee - the address where the funds will be transferred to.
* @param amount - the amount of ether to transfer to payee.
*/
function withdraw(address payable payee, uint256 amount) external;
}