Contract Name:
OfferFactory
Contract Source Code:
/**
* SPDX-License-Identifier: MIT
*
* Copyright (c) 2016-2019 zOS Global Limited
*
*/
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP. Does not include
* the optional functions; to access them see `ERC20Detailed`.
*/
interface IERC20 {
// Optional functions
function name() external view returns (string memory);
function symbol() external view returns (string memory);
function decimals() external view returns (uint8);
/**
* @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 `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a `Transfer` event.
*/
function transfer(address recipient, 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.
*
* > 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 `sender` to `recipient` 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 sender, address recipient, uint256 amount) external returns (bool);
/**
* @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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)
// Copied from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/extensions/draft-IERC20Permit.sol
pragma solidity ^0.8.0;
import "./IERC20.sol";
/**
* @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 is IERC20 {
/*//////////////////////////////////////////////////////////////
Custom errors
//////////////////////////////////////////////////////////////*/
/// Block timestamp must to be before deadline.
/// @param deadline The deadline of the permit.
/// @param blockTimestamp The timestamp of the execution block.
error Permit_DeadlineExpired(uint256 deadline, uint256 blockTimestamp);
/// Recovered address must be owner and not zero address.
/// @param signerAddress The recovered signer address.
error Permit_InvalidSigner(address signerAddress);
/**
* @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
pragma solidity ^0.8.0;
import "../ERC20/IERC20.sol";
import "./IOffer.sol";
interface IDraggable is IERC20 {
/*//////////////////////////////////////////////////////////////
Custom errors
//////////////////////////////////////////////////////////////*/
/// conversion factor has to be > 0 for this transaction.
error Draggable_NotBinding();
/// conversion factor has to be = 0 for this transaction.
error Draggable_IsBinding();
/// conversion factor can't be 0 if binding gets deactivated.
error Draggable_FactorZero();
/// the reported votes can't be > max voting tokens.
/// @param maxVotes The max voting tokens.
/// @param reportedVotes The actual reported votes.
error Draggable_TooManyVotes(uint256 maxVotes, uint256 reportedVotes);
/// there is still an open offer that has to be canceled first
error Draggable_OpenOffer();
/// For migration the quorum needs to be reached.
/// @param needed The needed quorum.
/// @param actual The current yes votes.
error Draggable_QuorumNotReached(uint256 needed, uint256 actual);
function wrapped() external view returns (IERC20);
function unwrap(uint256 amount) external;
function offer() external view returns (IOffer);
function oracle() external view returns (address);
function drag(address buyer, IERC20 currency) external;
function notifyOfferEnded() external;
function votingPower(address voter) external returns (uint256);
function totalVotingTokens() external view returns (uint256);
function notifyVoted(address voter) external;
function migrate() external;
function setOracle(address newOracle) external;
function migrateWithExternalApproval(address successor, uint256 additionalVotes) external;
function setTerms(string calldata _terms) external;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../ERC20/IERC20.sol";
interface IOffer {
/*//////////////////////////////////////////////////////////////
Custom errors
//////////////////////////////////////////////////////////////*/
/// Invalid msg.sender.
/// @param sender The msg.sender of the transaction.
error Offer_InvalidSender(address sender);
/// Offer needs to be still open.
error Offer_AlreadyAccepted();
/// Offer needs to be not accepted yet.
error Offer_NotAccepted();
/// Sender of the offer needs to have needed funds in his account.
error Offer_NotWellFunded();
/// New offer not valid. `newPrice` needs to be higher than `oldPrice`.
/// @param oldPrice Price of the old offer.
/// @param newPrice Price of the new offer.
error Offer_OldOfferBetter(uint256 oldPrice, uint256 newPrice);
/// Voting needs to be still open.
error Offer_VotingEnded();
/// Too many (External) reported votes. `reportedVotes` needs to be less or equal to `maxVotes`.
/// @param maxVotes The max possible votes for the token.
/// @param reportedVotes The external reported votes + circulating supply of the token.
error Offer_TooManyVotes(uint256 maxVotes, uint256 reportedVotes);
/// Competing offer needs to be in the same currency.
error Offer_OfferInWrongCurrency();
/// Offer got already killed.
error Offer_IsKilled();
/*//////////////////////////////////////////////////////////////
Function Interfaces
//////////////////////////////////////////////////////////////*/
function makeCompetingOffer(IOffer newOffer) external;
// if there is a token transfer while an offer is open, the votes get transfered too
function notifyMoved(address from, address to, uint256 value) external;
function currency() external view returns (IERC20);
function price() external view returns (uint256);
function isWellFunded() external view returns (bool);
function voteYes() external;
function voteNo() external;
function isKilled() external view returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../ERC20/IERC20.sol";
import "./IOffer.sol";
interface IOfferFactory {
function create(
bytes32 salt, address buyer, uint256 pricePerShare, IERC20 currency, uint256 quorum, uint256 votePeriod
) external payable returns (IOffer);
}
/**
* SPDX-License-Identifier: LicenseRef-Aktionariat
*
* MIT License with Automated License Fee Payments
*
* Copyright (c) 2022 Aktionariat AG (aktionariat.com)
*
* Permission is hereby granted to any person obtaining a copy of this software
* and associated documentation files (the "Software"), to deal in the Software
* without restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies of the
* Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - All automated license fee payments integrated into this and related Software
* are preserved.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
pragma solidity ^0.8.0;
import "../ERC20/IERC20.sol";
import "./IDraggable.sol";
import "./IOffer.sol";
import "../utils/SafeERC20.sol";
/**
* @title A public offer to acquire all tokens
* @author Luzius Meisser, [email protected]
*/
contract Offer is IOffer {
using SafeERC20 for IERC20;
address private constant LICENSE_FEE_ADDRESS = 0x29Fe8914e76da5cE2d90De98a64d0055f199d06D;
uint256 private constant AQUISITION_GRACE_PERIOD = 30 days; // buyer has thirty days to complete acquisition after voting ends
uint256 private constant BPS_MUL = 10000; // basis point multiplier to be used with quorum
uint256 public immutable quorum; // Percentage of votes needed to start drag-along process in BPS, i.e. 10'000 = 100%
IDraggable public immutable token;
address public immutable buyer; // who made the offer
IERC20 override public immutable currency;
uint256 override public immutable price; // the price offered per share
enum Vote { NONE, YES, NO } // Used internally, represents not voted yet or yes/no vote.
mapping (address => Vote) private votes; // Who votes what
uint256 public yesVotes; // total number of yes votes, including external votes
uint256 public noVotes; // total number of no votes, including external votes
uint256 public noExternal; // number of external no votes reported by oracle
uint256 public yesExternal; // number of external yes votes reported by oracle
uint256 public immutable voteEnd; // end of vote period in block time (seconds after 1.1.1970)
bool public isKilled; // indicator that contract disabled (replaces selfdestruct)
event VotesChanged(uint256 yesVotes, uint256 noVotes);
event OfferCreated(address indexed buyer, IDraggable indexed token, uint256 pricePerShare, IERC20 indexed currency);
event OfferEnded(address indexed buyer, bool executed, string message);
// Not checked here, but buyer should make sure it is well funded from the beginning
constructor(
address _buyer,
IDraggable _token,
uint256 _price,
IERC20 _currency,
uint256 _quorum,
uint256 _votePeriod
)
payable
{
buyer = _buyer;
token = _token;
currency = _currency;
price = _price;
quorum = _quorum;
// rely on time stamp is ok, no exact time stamp needed
// solhint-disable-next-line not-rely-on-time
voteEnd = block.timestamp + _votePeriod;
emit OfferCreated(_buyer, _token, _price, _currency);
// License Fee to Aktionariat AG, also ensures that offer is serious.
// Any circumvention of this license fee payment is a violation of the copyright terms.
payable(LICENSE_FEE_ADDRESS).transfer(5000 ether);
}
modifier onlyBuyer {
_checkSender(buyer);
_;
}
modifier onlyToken {
_checkSender(address(token));
_;
}
modifier onlyOracle {
_checkSender(token.oracle());
_;
}
modifier votingOpen {
if (!isVotingOpen()) {
revert Offer_VotingEnded();
}
_;
}
function makeCompetingOffer(IOffer betterOffer) external override onlyToken {
if (isAccepted()) {
revert Offer_AlreadyAccepted();
}
uint256 newPrice = betterOffer.price();
if (newPrice <= price) {
revert Offer_OldOfferBetter(price, newPrice);
}
if (currency != betterOffer.currency()) {
revert Offer_OfferInWrongCurrency();
}
if (!betterOffer.isWellFunded()) {
revert Offer_NotWellFunded();
}
kill(false, "replaced");
}
function hasExpired() internal view returns (bool) {
// rely on time stamp is ok, no exact time stamp needed
// solhint-disable-next-line not-rely-on-time
return block.timestamp > voteEnd + AQUISITION_GRACE_PERIOD;
}
function contest() external {
if (hasExpired()) {
kill(false, "expired");
} else if (isDeclined()) {
kill(false, "declined");
} else if (!isWellFunded()) {
kill(false, "lack of funds");
}
}
function cancel() external onlyBuyer {
kill(false, "cancelled");
}
function execute() external onlyBuyer {
if (isKilled) revert Offer_IsKilled();
if (!isAccepted()) revert Offer_NotAccepted();
uint256 totalPrice = getTotalPrice();
currency.safeTransferFrom(buyer, address(token), totalPrice);
token.drag(buyer, currency);
kill(true, "success");
}
function getTotalPrice() internal view returns (uint256) {
IERC20 tok = IERC20(address(token));
return (tok.totalSupply() - tok.balanceOf(buyer)) * price;
}
function isWellFunded() public view override returns (bool) {
uint256 buyerBalance = currency.balanceOf(buyer);
uint256 totalPrice = getTotalPrice();
return totalPrice <= buyerBalance;
}
function isAccepted() public view returns (bool) {
if (isVotingOpen()) {
// is it already clear that more than the quorum requiered will vote yes even though the vote is not over yet?
return yesVotes * BPS_MUL >= quorum * token.totalVotingTokens();
} else {
// did more than the quorum requiered votes say 'yes'?
return yesVotes * BPS_MUL >= quorum * (yesVotes + noVotes);
}
}
function isDeclined() public view returns (bool) {
if (isVotingOpen()) {
// is it already clear that 25% will vote no even though the vote is not over yet?
uint256 supply = token.totalVotingTokens();
return (supply - noVotes) * BPS_MUL < quorum * supply;
} else {
// did quorum% of all cast votes say 'no'?
return BPS_MUL * yesVotes < quorum * (yesVotes + noVotes);
}
}
function notifyMoved(address from, address to, uint256 value) external override onlyToken {
if (isVotingOpen()) {
Vote fromVoting = votes[from];
Vote toVoting = votes[to];
update(fromVoting, toVoting, value);
}
}
function update(Vote previousVote, Vote newVote, uint256 votes_) internal {
if (previousVote != newVote) {
if (previousVote == Vote.NO) {
noVotes -= votes_;
} else if (previousVote == Vote.YES) {
yesVotes -= votes_;
}
if (newVote == Vote.NO) {
noVotes += votes_;
} else if (newVote == Vote.YES) {
yesVotes += votes_;
}
emit VotesChanged(yesVotes, noVotes);
}
}
function isVotingOpen() public view returns (bool) {
// rely on time stamp is ok, no exact time stamp needed
// solhint-disable-next-line not-rely-on-time
return block.timestamp <= voteEnd && !isKilled;
}
/**
* Function to allow the oracle to report the votes of external votes (e.g. shares tokenized on other blockchains).
* This functions is idempotent and sets the number of external yes and no votes. So when more votes come in, the
* oracle should always report the total number of yes and no votes. Abstentions are not counted.
*/
function reportExternalVotes(uint256 yes, uint256 no) external onlyOracle votingOpen {
uint256 maxVotes = token.totalVotingTokens();
uint256 reportingVotes = yes + no + IERC20(address(token)).totalSupply();
if (reportingVotes > maxVotes) {
revert Offer_TooManyVotes(maxVotes, reportingVotes);
}
// adjust total votes taking into account that the oralce might have reported different counts before
yesVotes = yesVotes - yesExternal + yes;
noVotes = noVotes - noExternal + no;
// remember how the oracle voted in case the oracle later reports updated numbers
yesExternal = yes;
noExternal = no;
}
function voteYes() external override{
vote(Vote.YES);
}
function voteNo() external override{
vote(Vote.NO);
}
function vote(Vote newVote) internal votingOpen {
Vote previousVote = votes[msg.sender];
votes[msg.sender] = newVote;
if(previousVote == Vote.NONE){
token.notifyVoted(msg.sender);
}
update(previousVote, newVote, token.votingPower(msg.sender));
}
function hasVotedYes(address voter) external view returns (bool) {
return votes[voter] == Vote.YES;
}
function hasVotedNo(address voter) external view returns (bool) {
return votes[voter] == Vote.NO;
}
function kill(bool executed, string memory message) internal {
isKilled = true;
emit OfferEnded(buyer, executed, message);
token.notifyOfferEnded();
payable(buyer).call{value:address(this).balance}(""); // buyer is responsible to be able to receive Ether, else he can block cancellation
}
/**
* Checks if msg.sender is an authorized address.
* @param validSender The authorized address.
*/
function _checkSender(address validSender) internal view {
if (msg.sender != validSender) {
revert Offer_InvalidSender(msg.sender);
}
}
}
/**
* SPDX-License-Identifier: LicenseRef-Aktionariat
*
* MIT License with Automated License Fee Payments
*
* Copyright (c) 2022 Aktionariat AG (aktionariat.com)
*
* Permission is hereby granted to any person obtaining a copy of this software
* and associated documentation files (the "Software"), to deal in the Software
* without restriction, including without limitation the rights to use, copy,
* modify, merge, publish, distribute, sublicense, and/or sell copies of the
* Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* - The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
* - All automated license fee payments integrated into this and related Software
* are preserved.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
pragma solidity ^0.8.0;
import "./Offer.sol";
import "./IOffer.sol";
import "./IOfferFactory.sol";
contract OfferFactory is IOfferFactory{
// It must be possible to predict the address of the offer so one can pre-fund the allowance.
function predictOfferAddress(bytes32 salt, address buyer, IDraggable token, uint256 pricePerShare, IERC20 currency, uint256 quorum, uint256 votePeriod) external view returns (address) {
bytes32 initCodeHash = keccak256(abi.encodePacked(type(Offer).creationCode, abi.encode(buyer, token, pricePerShare, currency, quorum, votePeriod)));
bytes32 hashResult = keccak256(abi.encodePacked(bytes1(0xff), address(this), salt, initCodeHash));
return address(uint160(uint256(hashResult)));
}
// Do not call directly, msg.sender must be the token to be acquired
function create(bytes32 salt, address buyer, uint256 pricePerShare, IERC20 currency, uint256 quorum, uint256 votePeriod) override external payable returns (IOffer) {
IOffer offer = new Offer{value: msg.value, salt: salt}(buyer, IDraggable(msg.sender), pricePerShare, currency, quorum, votePeriod);
return offer;
}
}
// SPDX-License-Identifier: MIT
// Copied from https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Address.sol
// and modified it.
pragma solidity ^0.8.0;
library Address {
/// @param target Target address to call the function on.
error Address_NotTransferNorContract(address target);
/**
* @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/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 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 or custom error, it is bubbled
* up by this function (like regular Solidity function calls). However, if
* the call reverted with no returned reason, this function reverts with a
* {FailedInnerCall} error.
*
* 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.
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0);
}
function functionCallWithValue(address target, bytes memory data, uint256 weiValue) internal returns (bytes memory) {
if (data.length != 0 && !isContract(target)) {
revert Address_NotTransferNorContract(target);
}
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
if (success) {
return returndata;
} else if (returndata.length > 0) {
assembly{
revert (add (returndata, 0x20), mload (returndata))
}
} else {
revert("failed");
}
}
}
// SPDX-License-Identifier: MIT
// coppied and adjusted from OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.20;
import {IERC20} from "../ERC20/IERC20.sol";
import {IERC20Permit} from "../ERC20/IERC20Permit.sol";
import {Address} from "./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;
/**
* @dev An operation with an ERC20 token failed.
*/
error SafeERC20FailedOperation(address token);
/**
* @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
* non-reverting calls are assumed to be successful.
*/
function safeTransfer(IERC20 token, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeCall(token.transfer, (to, value)));
}
/**
* @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
* calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
*/
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeCall(token.transferFrom, (from, to, value)));
}
/**
* @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
* Revert on invalid signature.
*/
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);
if (nonceAfter != nonceBefore + 1) {
revert SafeERC20FailedOperation(address(token));
}
}
/**
* @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);
if (returndata.length != 0 && !abi.decode(returndata, (bool))) {
revert SafeERC20FailedOperation(address(token));
}
}
/**
* @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).
*
* This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
*/
function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
// 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 cannot use {Address-functionCall} here since this should return false
// and not revert is the subcall reverts.
(bool success, bytes memory returndata) = address(token).call(data);
return success && (returndata.length == 0 || abi.decode(returndata, (bool))) && address(token).code.length > 0;
}
}