Contract Name:
ProxyFactory
Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/utils/Address.sol";
contract ProxyFactory {
using SafeERC20 for IERC20;
using Address for address payable;
/// @dev See comment below for explanation of the proxy INIT_CODE
bytes private constant INIT_CODE =
hex"604080600a3d393df3fe"
hex"7300000000000000000000000000000000000000003d36602557"
hex"3d3d3d3d34865af1603156"
hex"5b363d3d373d3d363d855af4"
hex"5b3d82803e603c573d81fd5b3d81f3";
/// @dev The main address that the deployed proxies will forward to.
address payable public immutable mainLogicAddress;
address public immutable operatorAddress;
constructor(address payable ethDepositLogicAddr, address operatorAddr) {
require(ethDepositLogicAddr != address(0), "0x0 is an invalid address");
require(operatorAddr != address(0), "0x0 is an invalid address");
mainLogicAddress = ethDepositLogicAddr;
operatorAddress = operatorAddr;
}
/**
* @notice Event used to log the receiver address, token address, operator address, and amount when the returnBackErc20 was called
* @param toAddr The receiver address of the returned erc20 token
* @param tokenAddr The token address of the erc20 token
* @param operatorAddr The operator address which calls the function
* @param fromAddr The address which returnback Erc21
* @param amount The amount of the erc20 token which was returned
*/
event ReturnBackErc20(
address indexed toAddr,
address indexed tokenAddr,
address operatorAddr,
address indexed fromAddr,
uint256 amount
);
/**
* @notice Event used to log the receiver address, token address, operator address, and tokenId when the returnBackErc721 was called
* @param toAddr The receiver address of the returned erc721 token
* @param tokenAddr The token address of the erc721 token
* @param operatorAddr The operator address which calls the function
* @param fromAddr The address which returnback Erc721
* @param tokenId The tokenId of the erc721 token which was returned
*/
event ReturnBackErc721(
address indexed toAddr,
address indexed tokenAddr,
address operatorAddr,
address indexed fromAddr,
uint256 tokenId
);
/**
* @dev Modifier that will execute internal code block only if the sender is the operator account
*/
modifier onlyOperator() {
require(msg.sender == operatorAddress, "Unauthorized Operator");
_;
}
/**
* @dev batch creation for proxy contract
* @param from Represent the initial value of salt
* @param instanceAmount The amount of the creation of the proxy contract
* @return ethDepositProxyAddr The address array of new created proxy contracts
*/
function deployNewInstanceBatch(uint256 from, uint256 instanceAmount)
external
onlyOperator
returns (address[] memory)
{
// copy init code into memory
// and immutable EthDepositLogic address onto stack
bytes memory initCodeMem = INIT_CODE;
address payable addrStack = mainLogicAddress;
address dst;
address[] memory ethDepositProxyAddrs = new address[](instanceAmount);
// loop with times set by the instanceAmount
// i represent the salt of create2
for (uint256 i = from; i < from + instanceAmount; ++i) {
assembly {
// Get the position of the start of init code
let pos := add(initCodeMem, 0x20)
// grab the first 32 bytes
let first32 := mload(pos)
// shift the address bytes 8 bits left
let addrBytesShifted := shl(8, addrStack)
// bitwise OR them and add the address into the init code memory
mstore(pos, or(first32, addrBytesShifted))
// create the contract
dst := create2(
0, // Send no value to the contract
pos, // Deploy code starts at pos
74, // Deploy + runtime code is 74 bytes
i // 32 byte salt
)
// revert if failed
if eq(dst, 0) {
revert(0, 0)
}
}
ethDepositProxyAddrs[(i - from)] = dst; // store the created proxy address to array
}
return ethDepositProxyAddrs; // return the created proxy addrs
}
/**
* @notice External function for returning Erc20 token to specific address
* @dev Should be called by operator account
* @param erc20Addr The address of the erc20 token contract
* @param to The target address which received the erc20 token
* @param amount The amount of the erc20 token to return
*/
function returnBackErc20(
IERC20 erc20Addr,
address to,
uint256 amount
) external onlyOperator {
require(amount != 0, "0 is an invalid amount");
require(to != address(0), "0x0 is an invalid address");
uint256 erc20Balance = erc20Addr.balanceOf(address(this));
require(erc20Balance >= amount, "amount is invalid");
erc20Addr.safeTransfer(to, amount);
emit ReturnBackErc20(
to,
address(erc20Addr),
msg.sender,
address(this),
amount
);
}
/**
* @notice External function for returning erc721 token to specific address
* @dev Should be called by operator account,
* use transferFrom to make sure it can be returned to all specific contract addresses
* @param erc721Addr The address of the erc721 token contract
* @param to The target address which received the erc721 token
* @param tokenId The tokenId of the erc721 token to return
*/
function returnBackErc721(
IERC721 erc721Addr,
address to,
uint256 tokenId
) external onlyOperator {
require(to != address(0), "0x0 is an invalid address");
address owner = erc721Addr.ownerOf(tokenId);
require(owner == address(this), "sender is not tokenId owner");
erc721Addr.transferFrom(address(this), to, tokenId); // transfer Erc721 to specific address
emit ReturnBackErc721(
to,
address(erc721Addr),
msg.sender,
address(this),
tokenId
);
}
}
/*
// PROXY CONTRACT EXPLANATION
// DEPLOY CODE (will not be returned by web3.eth.getCode())
// STORE CONTRACT CODE IN MEMORY, THEN RETURN IT
POS | OPCODE | OPCODE TEXT | STACK |
00 | 6040 | PUSH1 0x40 | 0x40 |
02 | 80 | DUP1 | 0x40 0x40 |
03 | 600a | PUSH1 0x0a | 0x0a 0x40 0x40 |
05 | 3d | RETURNDATASIZE | 0x0 0x0a 0x40 0x40 |
06 | 39 | CODECOPY | 0x40 |
07 | 3d | RETURNDATASIZE | 0x0 0x40 |
08 | f3 | RETURN | |
09 | fe | INVALID | |
// START CONTRACT CODE
// Push the EthDepositLogic address on the stack for DUPing later
// Also pushing a 0x0 for DUPing later. (saves runtime AND deploy gas)
// Then use the calldata size as the decider for whether to jump or not
POS | OPCODE | OPCODE TEXT | STACK |
00 | 73... | PUSH20 ... | {ADDR} |
15 | 3d | RETURNDATASIZE | 0x0 {ADDR} |
16 | 36 | CALLDATASIZE | CDS 0x0 {ADDR} |
17 | 6025 | PUSH1 0x25 | 0x25 CDS 0x0 {ADDR} |
19 | 57 | JUMPI | 0x0 {ADDR} |
// If msg.data length === 0, CALL into address
// This way, the proxy contract address becomes msg.sender and we can use
// msg.sender in the Deposit Event
// This also gives us access to our EthDepositLogic storage (for forwarding address)
POS | OPCODE | OPCODE TEXT | STACK |
1A | 3d | RETURNDATASIZE | 0x0 0x0 {ADDR} |
1B | 3d | RETURNDATASIZE | 0x0 0x0 0x0 {ADDR} |
1C | 3d | RETURNDATASIZE | 0x0 0x0 0x0 0x0 {ADDR} |
1D | 3d | RETURNDATASIZE | 0x0 0x0 0x0 0x0 0x0 {ADDR} |
1E | 34 | CALLVALUE | VALUE 0x0 0x0 0x0 0x0 0x0 {ADDR} |
1F | 86 | DUP7 | {ADDR} VALUE 0x0 0x0 0x0 0x0 0x0 {ADDR} |
20 | 5a | GAS | GAS {ADDR} VALUE 0x0 0x0 0x0 0x0 0x0 {ADDR} |
21 | f1 | CALL | {RES} 0x0 {ADDR} |
22 | 6031 | PUSH1 0x31 | 0x31 {RES} 0x0 {ADDR} |
24 | 56 | JUMP | {RES} 0x0 {ADDR} |
// If msg.data length > 0, DELEGATECALL into address
// This will allow us to call gatherErc20 using the context of the proxy
// address itself.
POS | OPCODE | OPCODE TEXT | STACK |
25 | 5b | JUMPDEST | 0x0 {ADDR} |
26 | 36 | CALLDATASIZE | CDS 0x0 {ADDR} |
27 | 3d | RETURNDATASIZE | 0x0 CDS 0x0 {ADDR} |
28 | 3d | RETURNDATASIZE | 0x0 0x0 CDS 0x0 {ADDR} |
29 | 37 | CALLDATACOPY | 0x0 {ADDR} |
2A | 3d | RETURNDATASIZE | 0x0 0x0 {ADDR} |
2B | 3d | RETURNDATASIZE | 0x0 0x0 0x0 {ADDR} |
2C | 36 | CALLDATASIZE | CDS 0x0 0x0 0x0 {ADDR} |
2D | 3d | RETURNDATASIZE | 0x0 CDS 0x0 0x0 0x0 {ADDR} |
2E | 85 | DUP6 | {ADDR} 0x0 CDS 0x0 0x0 0x0 {ADDR} |
2F | 5a | GAS | GAS {ADDR} 0x0 CDS 0x0 0x0 0x0 {ADDR} |
30 | f4 | DELEGATECALL | {RES} 0x0 {ADDR} |
// We take the result of the call, load in the returndata,
// If call result == 0, failure, revert
// else success, return
POS | OPCODE | OPCODE TEXT | STACK |
31 | 5b | JUMPDEST | {RES} 0x0 {ADDR} |
32 | 3d | RETURNDATASIZE | RDS {RES} 0x0 {ADDR} |
33 | 82 | DUP3 | 0x0 RDS {RES} 0x0 {ADDR} |
34 | 80 | DUP1 | 0x0 0x0 RDS {RES} 0x0 {ADDR} |
35 | 3e | RETURNDATACOPY | {RES} 0x0 {ADDR} |
36 | 603c | PUSH1 0x3c | 0x3c {RES} 0x0 {ADDR} |
38 | 57 | JUMPI | 0x0 {ADDR} |
39 | 3d | RETURNDATASIZE | RDS 0x0 {ADDR} |
3A | 81 | DUP2 | 0x0 RDS 0x0 {ADDR} |
3B | fd | REVERT | 0x0 {ADDR} |
3C | 5b | JUMPDEST | 0x0 {ADDR} |
3D | 3d | RETURNDATASIZE | RDS 0x0 {ADDR} |
3E | 81 | DUP2 | 0x0 RDS 0x0 {ADDR} |
3F | f3 | RETURN | 0x0 {ADDR} |
*/
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC165 standard, as defined in the
* https://eips.ethereum.org/EIPS/eip-165[EIP].
*
* Implementers can declare support of contract interfaces, which can then be
* queried by others ({ERC165Checker}).
*
* For an implementation, see {ERC165}.
*/
interface IERC165 {
/**
* @dev Returns true if this contract implements the interface defined by
* `interfaceId`. See the corresponding
* https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
* to learn more about how these ids are created.
*
* This function call must use less than 30 000 gas.
*/
function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
// 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
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC721/IERC721.sol)
pragma solidity ^0.8.0;
import "../../utils/introspection/IERC165.sol";
/**
* @dev Required interface of an ERC721 compliant contract.
*/
interface IERC721 is IERC165 {
/**
* @dev Emitted when `tokenId` token is transferred from `from` to `to`.
*/
event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
/**
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
*/
event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
/**
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
*/
event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
/**
* @dev Returns the number of tokens in ``owner``'s account.
*/
function balanceOf(address owner) external view returns (uint256 balance);
/**
* @dev Returns the owner of the `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function ownerOf(uint256 tokenId) external view returns (address owner);
/**
* @dev Safely transfers `tokenId` token from `from` to `to`.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId,
bytes calldata data
) external;
/**
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
* are aware of the ERC721 protocol to prevent tokens from being forever locked.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId
) external;
/**
* @dev Transfers `tokenId` token from `from` to `to`.
*
* WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC721
* or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
* understand this adds an external call which potentially creates a reentrancy vulnerability.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address from,
address to,
uint256 tokenId
) external;
/**
* @dev Gives permission to `to` to transfer `tokenId` token to another account.
* The approval is cleared when the token is transferred.
*
* Only a single account can be approved at a time, so approving the zero address clears previous approvals.
*
* Requirements:
*
* - The caller must own the token or be an approved operator.
* - `tokenId` must exist.
*
* Emits an {Approval} event.
*/
function approve(address to, uint256 tokenId) external;
/**
* @dev Approve or remove `operator` as an operator for the caller.
* Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
*
* Requirements:
*
* - The `operator` cannot be the caller.
*
* Emits an {ApprovalForAll} event.
*/
function setApprovalForAll(address operator, bool _approved) external;
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function getApproved(uint256 tokenId) external view returns (address operator);
/**
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}
*/
function isApprovedForAll(address owner, address operator) external view returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.sol";
import "../../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using Address for address;
function safeTransfer(
IERC20 token,
address to,
uint256 value
) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(
IERC20 token,
address from,
address to,
uint256 value
) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(
IERC20 token,
address spender,
uint256 value
) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
require(
(value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
uint256 newAllowance = token.allowance(address(this), spender) + value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
uint256 newAllowance = oldAllowance - value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
}
function safePermit(
IERC20Permit token,
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) internal {
uint256 nonceBefore = token.nonces(owner);
token.permit(owner, spender, value, deadline, v, r, s);
uint256 nonceAfter = token.nonces(owner);
require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) {
// Return data is optional
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
* https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
*
* Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
* presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
* need to send a transaction, and thus is not required to hold Ether at all.
*/
interface IERC20Permit {
/**
* @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
* given ``owner``'s signed approval.
*
* IMPORTANT: The same issues {IERC20-approve} has related to transaction
* ordering also apply here.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `deadline` must be a timestamp in the future.
* - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
* over the EIP712-formatted function arguments.
* - the signature must use ``owner``'s current nonce (see {nonces}).
*
* For more information on the signature format, see the
* https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
* section].
*/
function permit(
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) external;
/**
* @dev Returns the current nonce for `owner`. This value must be
* included whenever a signature is generated for {permit}.
*
* Every successful call to {permit} increases ``owner``'s nonce by one. This
* prevents a signature from being used multiple times.
*/
function nonces(address owner) external view returns (uint256);
/**
* @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
*/
// solhint-disable-next-line func-name-mixedcase
function DOMAIN_SEPARATOR() external view returns (bytes32);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `from` to `to` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address from,
address to,
uint256 amount
) external returns (bool);
}