Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts/proxy/Clones.sol";
import "@openzeppelin/contracts-upgradeable/utils/ReentrancyGuardUpgradeable.sol";
import "./OwnerPausableUpgradeable.sol";
import "./SwapUtils.sol";
import "./AmplificationUtils.sol";
/**
* @title Swap - A StableSwap implementation in solidity.
* @notice This contract is responsible for custody of closely pegged assets (eg. group of stablecoins)
* and automatic market making system. Users become an LP (Liquidity Provider) by depositing their tokens
* in desired ratios for an exchange of the pool token that represents their share of the pool.
* Users can burn pool tokens and withdraw their share of token(s).
*
* Each time a swap between the pooled tokens happens, a set fee incurs which effectively gets
* distributed to the LPs.
*
* In case of emergencies, admin can pause additional deposits, swaps, or single-asset withdraws - which
* stops the ratio of the tokens in the pool from changing.
* Users can always withdraw their tokens via multi-asset withdraws.
*
* @dev Most of the logic is stored as a library `SwapUtils` for the sake of reducing contract's
* deployment size.
*/
contract Swap is OwnerPausableUpgradeable, ReentrancyGuardUpgradeable {
using SafeERC20 for IERC20;
using SafeMath for uint256;
using SwapUtils for SwapUtils.Swap;
using AmplificationUtils for SwapUtils.Swap;
// Struct storing data responsible for automatic market maker functionalities. In order to
// access this data, this contract uses SwapUtils library. For more details, see SwapUtils.sol
SwapUtils.Swap public swapStorage;
// Maps token address to an index in the pool. Used to prevent duplicate tokens in the pool.
// getTokenIndex function also relies on this mapping to retrieve token index.
mapping(address => uint8) private tokenIndexes;
/*** EVENTS ***/
// events replicated from SwapUtils to make the ABI easier for dumb
// clients
event TokenSwap(
address indexed buyer,
uint256 tokensSold,
uint256 tokensBought,
uint128 soldId,
uint128 boughtId
);
event AddLiquidity(
address indexed provider,
uint256[] tokenAmounts,
uint256[] fees,
uint256 invariant,
uint256 lpTokenSupply
);
event RemoveLiquidity(
address indexed provider,
uint256[] tokenAmounts,
uint256 lpTokenSupply
);
event RemoveLiquidityOne(
address indexed provider,
uint256 lpTokenAmount,
uint256 lpTokenSupply,
uint256 boughtId,
uint256 tokensBought
);
event RemoveLiquidityImbalance(
address indexed provider,
uint256[] tokenAmounts,
uint256[] fees,
uint256 invariant,
uint256 lpTokenSupply
);
event NewAdminFee(uint256 newAdminFee);
event NewSwapFee(uint256 newSwapFee);
event NewWithdrawFee(uint256 newWithdrawFee);
event NewFeeCollector(address newFeeCollector);
event RampA(
uint256 oldA,
uint256 newA,
uint256 initialTime,
uint256 futureTime
);
event StopRampA(uint256 currentA, uint256 time);
/**
* @notice Initializes this Swap contract with the given parameters.
* This will also clone a LPToken contract that represents users'
* LP positions. The owner of LPToken will be this contract - which means
* only this contract is allowed to mint/burn tokens.
*
* @param _pooledTokens an array of ERC20s this pool will accept
* @param decimals the decimals to use for each pooled token,
* eg 8 for WBTC. Cannot be larger than POOL_PRECISION_DECIMALS
* @param lpTokenName the long-form name of the token to be deployed
* @param lpTokenSymbol the short symbol for the token to be deployed
* @param _a the amplification coefficient * n * (n - 1). See the
* StableSwap paper for details
* @param _fee default swap fee to be initialized with
* @param _adminFee default adminFee to be initialized with
* @param lpTokenTargetAddress the address of an existing LPToken contract to use as a target
*/
function initialize(
IERC20[] memory _pooledTokens,
uint8[] memory decimals,
string memory lpTokenName,
string memory lpTokenSymbol,
uint256 _a,
uint256 _fee,
uint256 _adminFee,
address lpTokenTargetAddress
) public virtual initializer {
__OwnerPausable_init();
__ReentrancyGuard_init();
// Check _pooledTokens and precisions parameter
require(_pooledTokens.length > 1, "_pooledTokens.length <= 1");
require(_pooledTokens.length <= 32, "_pooledTokens.length > 32");
require(
_pooledTokens.length == decimals.length,
"_pooledTokens decimals mismatch"
);
uint256[] memory precisionMultipliers = new uint256[](decimals.length);
for (uint8 i = 0; i < _pooledTokens.length; i++) {
if (i > 0) {
// Check if index is already used. Check if 0th element is a duplicate.
require(
tokenIndexes[address(_pooledTokens[i])] == 0 &&
_pooledTokens[0] != _pooledTokens[i],
"Duplicate tokens"
);
}
require(
address(_pooledTokens[i]) != address(0),
"The 0 address isn't an ERC-20"
);
require(
decimals[i] <= SwapUtils.POOL_PRECISION_DECIMALS,
"Token decimals exceeds max"
);
precisionMultipliers[i] =
10 **
uint256(SwapUtils.POOL_PRECISION_DECIMALS).sub(
uint256(decimals[i])
);
tokenIndexes[address(_pooledTokens[i])] = i;
}
// Check _a, _fee, _adminFee, _withdrawFee parameters
require(_a < AmplificationUtils.MAX_A, "_a exceeds maximum");
require(_fee < SwapUtils.MAX_SWAP_FEE, "_fee exceeds maximum");
require(
_adminFee < SwapUtils.MAX_ADMIN_FEE,
"_adminFee exceeds maximum"
);
// Clone and initialize a LPToken contract
LPToken lpToken = LPToken(Clones.clone(lpTokenTargetAddress));
require(
lpToken.initialize(lpTokenName, lpTokenSymbol),
"could not init lpToken clone"
);
// Initialize swapStorage struct
swapStorage.lpToken = lpToken;
swapStorage.pooledTokens = _pooledTokens;
swapStorage.tokenPrecisionMultipliers = precisionMultipliers;
swapStorage.balances = new uint256[](_pooledTokens.length);
swapStorage.initialA = _a.mul(AmplificationUtils.A_PRECISION);
swapStorage.futureA = _a.mul(AmplificationUtils.A_PRECISION);
// swapStorage.initialATime = 0;
// swapStorage.futureATime = 0;
swapStorage.swapFee = _fee;
swapStorage.adminFee = _adminFee;
}
/*** MODIFIERS ***/
/**
* @notice Modifier to check deadline against current timestamp
* @param deadline latest timestamp to accept this transaction
*/
modifier deadlineCheck(uint256 deadline) {
require(block.timestamp <= deadline, "Deadline not met");
_;
}
/**
* @notice Modifier to check if the sender is the fee collector
*/
modifier onlyFeeCollector() {
require(swapStorage.feeCollector != address(0), "Fee collector is not set. Call setFeeCollector to set it first");
require(msg.sender == swapStorage.feeCollector, "Fee collector only!");
_;
}
/*** VIEW FUNCTIONS ***/
/**
* @notice Return A, the amplification coefficient * n * (n - 1)
* @dev See the StableSwap paper for details
* @return A parameter
*/
function getA() external view virtual returns (uint256) {
return swapStorage.getA();
}
/**
* @notice Return A in its raw precision form
* @dev See the StableSwap paper for details
* @return A parameter in its raw precision form
*/
function getAPrecise() external view virtual returns (uint256) {
return swapStorage.getAPrecise();
}
/**
* @notice Return address of the pooled token at given index. Reverts if tokenIndex is out of range.
* @param index the index of the token
* @return address of the token at given index
*/
function getToken(uint8 index) public view virtual returns (IERC20) {
require(index < swapStorage.pooledTokens.length, "Out of range");
return swapStorage.pooledTokens[index];
}
/**
* @notice Return the index of the given token address. Reverts if no matching
* token is found.
* @param tokenAddress address of the token
* @return the index of the given token address
*/
function getTokenIndex(address tokenAddress)
public
view
virtual
returns (uint8)
{
uint8 index = tokenIndexes[tokenAddress];
require(
address(getToken(index)) == tokenAddress,
"Token does not exist"
);
return index;
}
/**
* @notice Return current balance of the pooled token at given index
* @param index the index of the token
* @return current balance of the pooled token at given index with token's native precision
*/
function getTokenBalance(uint8 index)
external
view
virtual
returns (uint256)
{
require(index < swapStorage.pooledTokens.length, "Index out of range");
return swapStorage.balances[index];
}
/**
* @notice Get the virtual price, to help calculate profit
* @return the virtual price, scaled to the POOL_PRECISION_DECIMALS
*/
function getVirtualPrice() external view virtual returns (uint256) {
return swapStorage.getVirtualPrice();
}
/**
* @notice Calculate amount of tokens you receive on swap
* @param tokenIndexFrom the token the user wants to sell
* @param tokenIndexTo the token the user wants to buy
* @param dx the amount of tokens the user wants to sell. If the token charges
* a fee on transfers, use the amount that gets transferred after the fee.
* @return amount of tokens the user will receive
*/
function calculateSwap(
uint8 tokenIndexFrom,
uint8 tokenIndexTo,
uint256 dx
) external view virtual returns (uint256) {
return swapStorage.calculateSwap(tokenIndexFrom, tokenIndexTo, dx);
}
/**
* @notice A simple method to calculate prices from deposits or
* withdrawals, excluding fees but including slippage. This is
* helpful as an input into the various "min" parameters on calls
* to fight front-running
*
* @dev This shouldn't be used outside frontends for user estimates.
*
* @param amounts an array of token amounts to deposit or withdrawal,
* corresponding to pooledTokens. The amount should be in each
* pooled token's native precision. If a token charges a fee on transfers,
* use the amount that gets transferred after the fee.
* @param deposit whether this is a deposit or a withdrawal
* @return token amount the user will receive
*/
function calculateTokenAmount(uint256[] calldata amounts, bool deposit)
external
view
virtual
returns (uint256)
{
return swapStorage.calculateTokenAmount(amounts, deposit);
}
/**
* @notice A simple method to calculate amount of each underlying
* tokens that is returned upon burning given amount of LP tokens
* @param amount the amount of LP tokens that would be burned on withdrawal
* @return array of token balances that the user will receive
*/
function calculateRemoveLiquidity(uint256 amount)
external
view
virtual
returns (uint256[] memory)
{
return swapStorage.calculateRemoveLiquidity(amount);
}
/**
* @notice Calculate the amount of underlying token available to withdraw
* when withdrawing via only single token
* @param tokenAmount the amount of LP token to burn
* @param tokenIndex index of which token will be withdrawn
* @return availableTokenAmount calculated amount of underlying token
* available to withdraw
*/
function calculateRemoveLiquidityOneToken(
uint256 tokenAmount,
uint8 tokenIndex
) external view virtual returns (uint256 availableTokenAmount) {
return swapStorage.calculateWithdrawOneToken(tokenAmount, tokenIndex);
}
/**
* @notice This function reads the accumulated amount of admin fees of the token with given index
* @param index Index of the pooled token
* @return admin's token balance in the token's precision
*/
function getAdminBalance(uint256 index)
external
view
virtual
returns (uint256)
{
return swapStorage.getAdminBalance(index);
}
/*** STATE MODIFYING FUNCTIONS ***/
/**
* @notice Swap two tokens using this pool
* @param tokenIndexFrom the token the user wants to swap from
* @param tokenIndexTo the token the user wants to swap to
* @param dx the amount of tokens the user wants to swap from
* @param minDy the min amount the user would like to receive, or revert.
* @param deadline latest timestamp to accept this transaction
*/
function swap(
uint8 tokenIndexFrom,
uint8 tokenIndexTo,
uint256 dx,
uint256 minDy,
uint256 deadline
)
external
virtual
nonReentrant
whenNotPaused
deadlineCheck(deadline)
returns (uint256)
{
return swapStorage.swap(tokenIndexFrom, tokenIndexTo, dx, minDy);
}
/**
* @notice Add liquidity to the pool with the given amounts of tokens
* @param amounts the amounts of each token to add, in their native precision
* @param minToMint the minimum LP tokens adding this amount of liquidity
* should mint, otherwise revert. Handy for front-running mitigation
* @param deadline latest timestamp to accept this transaction
* @return amount of LP token user minted and received
*/
function addLiquidity(
uint256[] calldata amounts,
uint256 minToMint,
uint256 deadline
)
external
virtual
nonReentrant
whenNotPaused
deadlineCheck(deadline)
returns (uint256)
{
return swapStorage.addLiquidity(amounts, minToMint);
}
/**
* @notice Burn LP tokens to remove liquidity from the pool. Withdraw fee that decays linearly
* over period of 4 weeks since last deposit will apply.
* @dev Liquidity can always be removed, even when the pool is paused.
* @param amount the amount of LP tokens to burn
* @param minAmounts the minimum amounts of each token in the pool
* acceptable for this burn. Useful as a front-running mitigation
* @param deadline latest timestamp to accept this transaction
* @return amounts of tokens user received
*/
function removeLiquidity(
uint256 amount,
uint256[] calldata minAmounts,
uint256 deadline
)
external
virtual
nonReentrant
deadlineCheck(deadline)
returns (uint256[] memory)
{
return swapStorage.removeLiquidity(amount, minAmounts);
}
/**
* @notice Remove liquidity from the pool all in one token. Withdraw fee that decays linearly
* over period of 4 weeks since last deposit will apply.
* @param tokenAmount the amount of lp token to burn
* @param tokenIndex the index of the token you want to receive
* @param minAmount the minimum amount to withdraw, otherwise revert
* @param deadline latest timestamp to accept this transaction
* @return amount of chosen token user received
*/
function removeLiquidityOneToken(
uint256 tokenAmount,
uint8 tokenIndex,
uint256 minAmount,
uint256 deadline
)
external
virtual
nonReentrant
whenNotPaused
deadlineCheck(deadline)
returns (uint256)
{
return
swapStorage.removeLiquidityOneToken(
tokenAmount,
tokenIndex,
minAmount
);
}
/**
* @notice Remove liquidity from the pool, weighted differently than the
* pool's current balances. Withdraw fee that decays linearly
* over period of 4 weeks since last deposit will apply.
* @param amounts how much of each token to withdraw
* @param maxBurnAmount the max LP token provider is willing to pay to
* remove liquidity. Useful as a front-running mitigation.
* @param deadline latest timestamp to accept this transaction
* @return amount of LP tokens burned
*/
function removeLiquidityImbalance(
uint256[] calldata amounts,
uint256 maxBurnAmount,
uint256 deadline
)
external
virtual
nonReentrant
whenNotPaused
deadlineCheck(deadline)
returns (uint256)
{
return swapStorage.removeLiquidityImbalance(amounts, maxBurnAmount);
}
/*** ADMIN FUNCTIONS ***/
/**
* @notice Withdraw all admin fees to the fee collector address.
*/
function withdrawAdminFees() external onlyFeeCollector {
swapStorage.withdrawAdminFees(swapStorage.feeCollector);
}
/**
* @notice Update the admin fee. Admin fee takes portion of the swap fee.
* @param newAdminFee new admin fee to be applied on future transactions
*/
function setAdminFee(uint256 newAdminFee) external onlyOwner {
swapStorage.setAdminFee(newAdminFee);
}
/**
* @notice Update the fee collector address
* @param newFeeCollector new address as fee collector
*/
function setFeeCollector(address newFeeCollector) external onlyOwner {
swapStorage.setFeeCollector(newFeeCollector);
}
/**
* @notice Update the swap fee to be applied on swaps
* @param newSwapFee new swap fee to be applied on future transactions
*/
function setSwapFee(uint256 newSwapFee) external onlyOwner {
swapStorage.setSwapFee(newSwapFee);
}
/**
* @notice Start ramping up or down A parameter towards given futureA and futureTime
* Checks if the change is too rapid, and commits the new A value only when it falls under
* the limit range.
* @param futureA the new A to ramp towards
* @param futureTime timestamp when the new A should be reached
*/
function rampA(uint256 futureA, uint256 futureTime) external onlyOwner {
swapStorage.rampA(futureA, futureTime);
}
/**
* @notice Stop ramping A immediately. Reverts if ramp A is already stopped.
*/
function stopRampA() external onlyOwner {
swapStorage.stopRampA();
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
/**
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b > a) return (false, 0);
return (true, a - b);
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) return (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b == 0) return (false, 0);
return (true, a / b);
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b == 0) return (false, 0);
return (true, a % b);
}
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
require(b <= a, "SafeMath: subtraction overflow");
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) return 0;
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
require(b > 0, "SafeMath: division by zero");
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
require(b > 0, "SafeMath: modulo by zero");
return a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
return a - b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
* division by zero. The result is rounded towards zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryDiv}.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
return a % b;
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "./IERC20.sol";
import "../../math/SafeMath.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 SafeMath for uint256;
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'
// solhint-disable-next-line max-line-length
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).add(value);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
/**
* @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
// solhint-disable-next-line max-line-length
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev https://eips.ethereum.org/EIPS/eip-1167[EIP 1167] is a standard for
* deploying minimal proxy contracts, also known as "clones".
*
* > To simply and cheaply clone contract functionality in an immutable way, this standard specifies
* > a minimal bytecode implementation that delegates all calls to a known, fixed address.
*
* The library includes functions to deploy a proxy using either `create` (traditional deployment) or `create2`
* (salted deterministic deployment). It also includes functions to predict the addresses of clones deployed using the
* deterministic method.
*
* _Available since v3.4._
*/
library Clones {
/**
* @dev Deploys and returns the address of a clone that mimics the behaviour of `master`.
*
* This function uses the create opcode, which should never revert.
*/
function clone(address master) internal returns (address instance) {
// solhint-disable-next-line no-inline-assembly
assembly {
let ptr := mload(0x40)
mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
mstore(add(ptr, 0x14), shl(0x60, master))
mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000)
instance := create(0, ptr, 0x37)
}
require(instance != address(0), "ERC1167: create failed");
}
/**
* @dev Deploys and returns the address of a clone that mimics the behaviour of `master`.
*
* This function uses the create2 opcode and a `salt` to deterministically deploy
* the clone. Using the same `master` and `salt` multiple time will revert, since
* the clones cannot be deployed twice at the same address.
*/
function cloneDeterministic(address master, bytes32 salt) internal returns (address instance) {
// solhint-disable-next-line no-inline-assembly
assembly {
let ptr := mload(0x40)
mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
mstore(add(ptr, 0x14), shl(0x60, master))
mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000)
instance := create2(0, ptr, 0x37, salt)
}
require(instance != address(0), "ERC1167: create2 failed");
}
/**
* @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
*/
function predictDeterministicAddress(address master, bytes32 salt, address deployer) internal pure returns (address predicted) {
// solhint-disable-next-line no-inline-assembly
assembly {
let ptr := mload(0x40)
mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
mstore(add(ptr, 0x14), shl(0x60, master))
mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf3ff00000000000000000000000000000000)
mstore(add(ptr, 0x38), shl(0x60, deployer))
mstore(add(ptr, 0x4c), salt)
mstore(add(ptr, 0x6c), keccak256(ptr, 0x37))
predicted := keccak256(add(ptr, 0x37), 0x55)
}
}
/**
* @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
*/
function predictDeterministicAddress(address master, bytes32 salt) internal view returns (address predicted) {
return predictDeterministicAddress(master, salt, address(this));
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../proxy/Initializable.sol";
/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*
* TIP: If you would like to learn more about reentrancy and alternative ways
* to protect against it, check out our blog post
* https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
*/
abstract contract ReentrancyGuardUpgradeable is Initializable {
// Booleans are more expensive than uint256 or any type that takes up a full
// word because each write operation emits an extra SLOAD to first read the
// slot's contents, replace the bits taken up by the boolean, and then write
// back. This is the compiler's defense against contract upgrades and
// pointer aliasing, and it cannot be disabled.
// The values being non-zero value makes deployment a bit more expensive,
// but in exchange the refund on every call to nonReentrant will be lower in
// amount. Since refunds are capped to a percentage of the total
// transaction's gas, it is best to keep them low in cases like this one, to
// increase the likelihood of the full refund coming into effect.
uint256 private constant _NOT_ENTERED = 1;
uint256 private constant _ENTERED = 2;
uint256 private _status;
function __ReentrancyGuard_init() internal initializer {
__ReentrancyGuard_init_unchained();
}
function __ReentrancyGuard_init_unchained() internal initializer {
_status = _NOT_ENTERED;
}
/**
* @dev Prevents a contract from calling itself, directly or indirectly.
* Calling a `nonReentrant` function from another `nonReentrant`
* function is not supported. It is possible to prevent this from happening
* by making the `nonReentrant` function external, and make it call a
* `private` function that does the actual work.
*/
modifier nonReentrant() {
// On the first call to nonReentrant, _notEntered will be true
require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
_;
// By storing the original value once again, a refund is triggered (see
// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
uint256[49] private __gap;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/utils/PausableUpgradeable.sol";
/**
* @title OwnerPausable
* @notice An ownable contract allows the owner to pause and unpause the
* contract without a delay.
* @dev Only methods using the provided modifiers will be paused.
*/
abstract contract OwnerPausableUpgradeable is
OwnableUpgradeable,
PausableUpgradeable
{
function __OwnerPausable_init() internal initializer {
__Context_init_unchained();
__Ownable_init_unchained();
__Pausable_init_unchained();
}
/**
* @notice Pause the contract. Revert if already paused.
*/
function pause() external onlyOwner {
PausableUpgradeable._pause();
}
/**
* @notice Unpause the contract. Revert if already unpaused.
*/
function unpause() external onlyOwner {
PausableUpgradeable._unpause();
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "./AmplificationUtils.sol";
import "./LPToken.sol";
import "./MathUtils.sol";
/**
* @title SwapUtils library
* @notice A library to be used within Swap.sol. Contains functions responsible for custody and AMM functionalities.
* @dev Contracts relying on this library must initialize SwapUtils.Swap struct then use this library
* for SwapUtils.Swap struct. Note that this library contains both functions called by users and admins.
* Admin functions should be protected within contracts using this library.
*/
library SwapUtils {
using SafeERC20 for IERC20;
using SafeMath for uint256;
using MathUtils for uint256;
/*** EVENTS ***/
event TokenSwap(
address indexed buyer,
uint256 tokensSold,
uint256 tokensBought,
uint128 soldId,
uint128 boughtId
);
event AddLiquidity(
address indexed provider,
uint256[] tokenAmounts,
uint256[] fees,
uint256 invariant,
uint256 lpTokenSupply
);
event RemoveLiquidity(
address indexed provider,
uint256[] tokenAmounts,
uint256 lpTokenSupply
);
event RemoveLiquidityOne(
address indexed provider,
uint256 lpTokenAmount,
uint256 lpTokenSupply,
uint256 boughtId,
uint256 tokensBought
);
event RemoveLiquidityImbalance(
address indexed provider,
uint256[] tokenAmounts,
uint256[] fees,
uint256 invariant,
uint256 lpTokenSupply
);
event NewAdminFee(uint256 newAdminFee);
event NewSwapFee(uint256 newSwapFee);
event NewFeeCollector(address newFeeCollector);
struct Swap {
// variables around the ramp management of A,
// the amplification coefficient * n * (n - 1)
// see https://www.curve.fi/stableswap-paper.pdf for details
uint256 initialA;
uint256 futureA;
uint256 initialATime;
uint256 futureATime;
// fee calculation
uint256 swapFee;
uint256 adminFee;
LPToken lpToken;
// contract references for all tokens being pooled
IERC20[] pooledTokens;
// multipliers for each pooled token's precision to get to POOL_PRECISION_DECIMALS
// for example, TBTC has 18 decimals, so the multiplier should be 1. WBTC
// has 8, so the multiplier should be 10 ** 18 / 10 ** 8 => 10 ** 10
uint256[] tokenPrecisionMultipliers;
// the pool balance of each token, in the token's precision
// the contract's actual token balance might differ
uint256[] balances;
// The address to collect the admin fee
address feeCollector;
}
// Struct storing variables used in calculations in the
// calculateWithdrawOneTokenDY function to avoid stack too deep errors
struct CalculateWithdrawOneTokenDYInfo {
uint256 d0;
uint256 d1;
uint256 newY;
uint256 feePerToken;
uint256 preciseA;
}
// Struct storing variables used in calculations in the
// {add,remove}Liquidity functions to avoid stack too deep errors
struct ManageLiquidityInfo {
uint256 d0;
uint256 d1;
uint256 d2;
uint256 preciseA;
LPToken lpToken;
uint256 totalSupply;
uint256[] balances;
uint256[] multipliers;
}
// the precision all pools tokens will be converted to
uint8 public constant POOL_PRECISION_DECIMALS = 18;
// the denominator used to calculate admin and LP fees. For example, an
// LP fee might be something like tradeAmount.mul(fee).div(FEE_DENOMINATOR)
uint256 private constant FEE_DENOMINATOR = 10**10;
// Max swap fee is 1% or 100bps of each swap
uint256 public constant MAX_SWAP_FEE = 10**8;
// Max adminFee is 100% of the swapFee
// adminFee does not add additional fee on top of swapFee
// Instead it takes a certain % of the swapFee. Therefore it has no impact on the
// users but only on the earnings of LPs
uint256 public constant MAX_ADMIN_FEE = 10**10;
// Constant value used as max loop limit
uint256 private constant MAX_LOOP_LIMIT = 256;
/*** VIEW & PURE FUNCTIONS ***/
function _getAPrecise(Swap storage self) internal view returns (uint256) {
return AmplificationUtils._getAPrecise(self);
}
/**
* @notice Calculate the dy, the amount of selected token that user receives and
* the fee of withdrawing in one token
* @param tokenAmount the amount of lp token to burn
* @param tokenIndex which token will be withdrawn
* @param self Swap struct to read from
* @return the amount of token user will receive
*/
function calculateWithdrawOneToken(
Swap storage self,
uint256 tokenAmount,
uint8 tokenIndex
) external view returns (uint256) {
(uint256 availableTokenAmount, ) = _calculateWithdrawOneToken(
self,
tokenAmount,
tokenIndex,
self.lpToken.totalSupply()
);
return availableTokenAmount;
}
function _calculateWithdrawOneToken(
Swap storage self,
uint256 tokenAmount,
uint8 tokenIndex,
uint256 totalSupply
) internal view returns (uint256, uint256) {
uint256 dy;
uint256 newY;
uint256 currentY;
(dy, newY, currentY) = calculateWithdrawOneTokenDY(
self,
tokenIndex,
tokenAmount,
totalSupply
);
// dy_0 (without fees)
// dy, dy_0 - dy
uint256 dySwapFee = currentY
.sub(newY)
.div(self.tokenPrecisionMultipliers[tokenIndex])
.sub(dy);
return (dy, dySwapFee);
}
/**
* @notice Calculate the dy of withdrawing in one token
* @param self Swap struct to read from
* @param tokenIndex which token will be withdrawn
* @param tokenAmount the amount of lp token to burn
* @return the d and the new y after withdrawing one token
*/
function calculateWithdrawOneTokenDY(
Swap storage self,
uint8 tokenIndex,
uint256 tokenAmount,
uint256 totalSupply
)
internal
view
returns (
uint256,
uint256,
uint256
)
{
// Get the current D, then solve the stableswap invariant
// y_i for D - tokenAmount
uint256[] memory xp = _xp(self);
require(tokenIndex < xp.length, "Token index out of range");
CalculateWithdrawOneTokenDYInfo
memory v = CalculateWithdrawOneTokenDYInfo(0, 0, 0, 0, 0);
v.preciseA = _getAPrecise(self);
v.d0 = getD(xp, v.preciseA);
v.d1 = v.d0.sub(tokenAmount.mul(v.d0).div(totalSupply));
v.newY = getYD(v.preciseA, tokenIndex, xp, v.d1);
uint256[] memory xpReduced = new uint256[](xp.length);
v.feePerToken = _feePerToken(self.swapFee, xp.length);
for (uint256 i = 0; i < xp.length; i++) {
uint256 xpi = xp[i];
// if i == tokenIndex, dxExpected = xp[i] * d1 / d0 - newY
// else dxExpected = xp[i] - (xp[i] * d1 / d0)
// xpReduced[i] -= dxExpected * fee / FEE_DENOMINATOR
xpReduced[i] = xpi.sub(
(
(i == tokenIndex)
? xpi.mul(v.d1).div(v.d0).sub(v.newY)
: xpi.sub(xpi.mul(v.d1).div(v.d0))
).mul(v.feePerToken).div(FEE_DENOMINATOR)
);
}
uint256 dy = xpReduced[tokenIndex].sub(
getYD(v.preciseA, tokenIndex, xpReduced, v.d1)
);
dy = dy.sub(1).div(self.tokenPrecisionMultipliers[tokenIndex]);
return (dy, v.newY, xp[tokenIndex]);
}
/**
* @notice Calculate the price of a token in the pool with given
* precision-adjusted balances and a particular D.
*
* @dev This is accomplished via solving the invariant iteratively.
* See the StableSwap paper and Curve.fi implementation for further details.
*
* x_1**2 + x1 * (sum' - (A*n**n - 1) * D / (A * n**n)) = D ** (n + 1) / (n ** (2 * n) * prod' * A)
* x_1**2 + b*x_1 = c
* x_1 = (x_1**2 + c) / (2*x_1 + b)
*
* @param a the amplification coefficient * n * (n - 1). See the StableSwap paper for details.
* @param tokenIndex Index of token we are calculating for.
* @param xp a precision-adjusted set of pool balances. Array should be
* the same cardinality as the pool.
* @param d the stableswap invariant
* @return the price of the token, in the same precision as in xp
*/
function getYD(
uint256 a,
uint8 tokenIndex,
uint256[] memory xp,
uint256 d
) internal pure returns (uint256) {
uint256 numTokens = xp.length;
require(tokenIndex < numTokens, "Token not found");
uint256 c = d;
uint256 s;
uint256 nA = a.mul(numTokens);
for (uint256 i = 0; i < numTokens; i++) {
if (i != tokenIndex) {
s = s.add(xp[i]);
c = c.mul(d).div(xp[i].mul(numTokens));
// If we were to protect the division loss we would have to keep the denominator separate
// and divide at the end. However this leads to overflow with large numTokens or/and D.
// c = c * D * D * D * ... overflow!
}
}
c = c.mul(d).mul(AmplificationUtils.A_PRECISION).div(nA.mul(numTokens));
uint256 b = s.add(d.mul(AmplificationUtils.A_PRECISION).div(nA));
uint256 yPrev;
uint256 y = d;
for (uint256 i = 0; i < MAX_LOOP_LIMIT; i++) {
yPrev = y;
y = y.mul(y).add(c).div(y.mul(2).add(b).sub(d));
if (y.within1(yPrev)) {
return y;
}
}
revert("Approximation did not converge");
}
/**
* @notice Get D, the StableSwap invariant, based on a set of balances and a particular A.
* @param xp a precision-adjusted set of pool balances. Array should be the same cardinality
* as the pool.
* @param a the amplification coefficient * n * (n - 1) in A_PRECISION.
* See the StableSwap paper for details
* @return the invariant, at the precision of the pool
*/
function getD(uint256[] memory xp, uint256 a)
internal
pure
returns (uint256)
{
uint256 numTokens = xp.length;
uint256 s;
for (uint256 i = 0; i < numTokens; i++) {
s = s.add(xp[i]);
}
if (s == 0) {
return 0;
}
uint256 prevD;
uint256 d = s;
uint256 nA = a.mul(numTokens);
for (uint256 i = 0; i < MAX_LOOP_LIMIT; i++) {
uint256 dP = d;
for (uint256 j = 0; j < numTokens; j++) {
dP = dP.mul(d).div(xp[j].mul(numTokens));
// If we were to protect the division loss we would have to keep the denominator separate
// and divide at the end. However this leads to overflow with large numTokens or/and D.
// dP = dP * D * D * D * ... overflow!
}
prevD = d;
d = nA
.mul(s)
.div(AmplificationUtils.A_PRECISION)
.add(dP.mul(numTokens))
.mul(d)
.div(
nA
.sub(AmplificationUtils.A_PRECISION)
.mul(d)
.div(AmplificationUtils.A_PRECISION)
.add(numTokens.add(1).mul(dP))
);
if (d.within1(prevD)) {
return d;
}
}
// Convergence should occur in 4 loops or less. If this is reached, there may be something wrong
// with the pool. If this were to occur repeatedly, LPs should withdraw via `removeLiquidity()`
// function which does not rely on D.
revert("D does not converge");
}
/**
* @notice Given a set of balances and precision multipliers, return the
* precision-adjusted balances.
*
* @param balances an array of token balances, in their native precisions.
* These should generally correspond with pooled tokens.
*
* @param precisionMultipliers an array of multipliers, corresponding to
* the amounts in the balances array. When multiplied together they
* should yield amounts at the pool's precision.
*
* @return an array of amounts "scaled" to the pool's precision
*/
function _xp(
uint256[] memory balances,
uint256[] memory precisionMultipliers
) internal pure returns (uint256[] memory) {
uint256 numTokens = balances.length;
require(
numTokens == precisionMultipliers.length,
"Balances must match multipliers"
);
uint256[] memory xp = new uint256[](numTokens);
for (uint256 i = 0; i < numTokens; i++) {
xp[i] = balances[i].mul(precisionMultipliers[i]);
}
return xp;
}
/**
* @notice Return the precision-adjusted balances of all tokens in the pool
* @param self Swap struct to read from
* @return the pool balances "scaled" to the pool's precision, allowing
* them to be more easily compared.
*/
function _xp(Swap storage self) internal view returns (uint256[] memory) {
return _xp(self.balances, self.tokenPrecisionMultipliers);
}
/**
* @notice Get the virtual price, to help calculate profit
* @param self Swap struct to read from
* @return the virtual price, scaled to precision of POOL_PRECISION_DECIMALS
*/
function getVirtualPrice(Swap storage self)
external
view
returns (uint256)
{
uint256 d = getD(_xp(self), _getAPrecise(self));
LPToken lpToken = self.lpToken;
uint256 supply = lpToken.totalSupply();
if (supply > 0) {
return d.mul(10**uint256(POOL_PRECISION_DECIMALS)).div(supply);
}
return 0;
}
/**
* @notice Calculate the new balances of the tokens given the indexes of the token
* that is swapped from (FROM) and the token that is swapped to (TO).
* This function is used as a helper function to calculate how much TO token
* the user should receive on swap.
*
* @param preciseA precise form of amplification coefficient
* @param tokenIndexFrom index of FROM token
* @param tokenIndexTo index of TO token
* @param x the new total amount of FROM token
* @param xp balances of the tokens in the pool
* @return the amount of TO token that should remain in the pool
*/
function getY(
uint256 preciseA,
uint8 tokenIndexFrom,
uint8 tokenIndexTo,
uint256 x,
uint256[] memory xp
) internal pure returns (uint256) {
uint256 numTokens = xp.length;
require(
tokenIndexFrom != tokenIndexTo,
"Can't compare token to itself"
);
require(
tokenIndexFrom < numTokens && tokenIndexTo < numTokens,
"Tokens must be in pool"
);
uint256 d = getD(xp, preciseA);
uint256 c = d;
uint256 s;
uint256 nA = numTokens.mul(preciseA);
uint256 _x;
for (uint256 i = 0; i < numTokens; i++) {
if (i == tokenIndexFrom) {
_x = x;
} else if (i != tokenIndexTo) {
_x = xp[i];
} else {
continue;
}
s = s.add(_x);
c = c.mul(d).div(_x.mul(numTokens));
// If we were to protect the division loss we would have to keep the denominator separate
// and divide at the end. However this leads to overflow with large numTokens or/and D.
// c = c * D * D * D * ... overflow!
}
c = c.mul(d).mul(AmplificationUtils.A_PRECISION).div(nA.mul(numTokens));
uint256 b = s.add(d.mul(AmplificationUtils.A_PRECISION).div(nA));
uint256 yPrev;
uint256 y = d;
// iterative approximation
for (uint256 i = 0; i < MAX_LOOP_LIMIT; i++) {
yPrev = y;
y = y.mul(y).add(c).div(y.mul(2).add(b).sub(d));
if (y.within1(yPrev)) {
return y;
}
}
revert("Approximation did not converge");
}
/**
* @notice Externally calculates a swap between two tokens.
* @param self Swap struct to read from
* @param tokenIndexFrom the token to sell
* @param tokenIndexTo the token to buy
* @param dx the number of tokens to sell. If the token charges a fee on transfers,
* use the amount that gets transferred after the fee.
* @return dy the number of tokens the user will get
*/
function calculateSwap(
Swap storage self,
uint8 tokenIndexFrom,
uint8 tokenIndexTo,
uint256 dx
) external view returns (uint256 dy) {
(dy, ) = _calculateSwap(
self,
tokenIndexFrom,
tokenIndexTo,
dx,
self.balances
);
}
/**
* @notice Internally calculates a swap between two tokens.
*
* @dev The caller is expected to transfer the actual amounts (dx and dy)
* using the token contracts.
*
* @param self Swap struct to read from
* @param tokenIndexFrom the token to sell
* @param tokenIndexTo the token to buy
* @param dx the number of tokens to sell. If the token charges a fee on transfers,
* use the amount that gets transferred after the fee.
* @return dy the number of tokens the user will get
* @return dyFee the associated fee
*/
function _calculateSwap(
Swap storage self,
uint8 tokenIndexFrom,
uint8 tokenIndexTo,
uint256 dx,
uint256[] memory balances
) internal view returns (uint256 dy, uint256 dyFee) {
uint256[] memory multipliers = self.tokenPrecisionMultipliers;
uint256[] memory xp = _xp(balances, multipliers);
require(
tokenIndexFrom < xp.length && tokenIndexTo < xp.length,
"Token index out of range"
);
uint256 x = dx.mul(multipliers[tokenIndexFrom]).add(xp[tokenIndexFrom]);
uint256 y = getY(
_getAPrecise(self),
tokenIndexFrom,
tokenIndexTo,
x,
xp
);
dy = xp[tokenIndexTo].sub(y).sub(1);
dyFee = dy.mul(self.swapFee).div(FEE_DENOMINATOR);
dy = dy.sub(dyFee).div(multipliers[tokenIndexTo]);
}
/**
* @notice A simple method to calculate amount of each underlying
* tokens that is returned upon burning given amount of
* LP tokens
*
* @param amount the amount of LP tokens that would to be burned on
* withdrawal
* @return array of amounts of tokens user will receive
*/
function calculateRemoveLiquidity(Swap storage self, uint256 amount)
external
view
returns (uint256[] memory)
{
return
_calculateRemoveLiquidity(
self.balances,
amount,
self.lpToken.totalSupply()
);
}
function _calculateRemoveLiquidity(
uint256[] memory balances,
uint256 amount,
uint256 totalSupply
) internal pure returns (uint256[] memory) {
require(amount <= totalSupply, "Cannot exceed total supply");
uint256[] memory amounts = new uint256[](balances.length);
for (uint256 i = 0; i < balances.length; i++) {
amounts[i] = balances[i].mul(amount).div(totalSupply);
}
return amounts;
}
/**
* @notice A simple method to calculate prices from deposits or
* withdrawals, excluding fees but including slippage. This is
* helpful as an input into the various "min" parameters on calls
* to fight front-running
*
* @dev This shouldn't be used outside frontends for user estimates.
*
* @param self Swap struct to read from
* @param amounts an array of token amounts to deposit or withdrawal,
* corresponding to pooledTokens. The amount should be in each
* pooled token's native precision. If a token charges a fee on transfers,
* use the amount that gets transferred after the fee.
* @param deposit whether this is a deposit or a withdrawal
* @return if deposit was true, total amount of lp token that will be minted and if
* deposit was false, total amount of lp token that will be burned
*/
function calculateTokenAmount(
Swap storage self,
uint256[] calldata amounts,
bool deposit
) external view returns (uint256) {
uint256 a = _getAPrecise(self);
uint256[] memory balances = self.balances;
uint256[] memory multipliers = self.tokenPrecisionMultipliers;
uint256 d0 = getD(_xp(balances, multipliers), a);
for (uint256 i = 0; i < balances.length; i++) {
if (deposit) {
balances[i] = balances[i].add(amounts[i]);
} else {
balances[i] = balances[i].sub(
amounts[i],
"Cannot withdraw more than available"
);
}
}
uint256 d1 = getD(_xp(balances, multipliers), a);
uint256 totalSupply = self.lpToken.totalSupply();
if (deposit) {
return d1.sub(d0).mul(totalSupply).div(d0);
} else {
return d0.sub(d1).mul(totalSupply).div(d0);
}
}
/**
* @notice return accumulated amount of admin fees of the token with given index
* @param self Swap struct to read from
* @param index Index of the pooled token
* @return admin balance in the token's precision
*/
function getAdminBalance(Swap storage self, uint256 index)
external
view
returns (uint256)
{
require(index < self.pooledTokens.length, "Token index out of range");
return
self.pooledTokens[index].balanceOf(address(this)).sub(
self.balances[index]
);
}
/**
* @notice internal helper function to calculate fee per token multiplier used in
* swap fee calculations
* @param swapFee swap fee for the tokens
* @param numTokens number of tokens pooled
*/
function _feePerToken(uint256 swapFee, uint256 numTokens)
internal
pure
returns (uint256)
{
return swapFee.mul(numTokens).div(numTokens.sub(1).mul(4));
}
/*** STATE MODIFYING FUNCTIONS ***/
/**
* @notice swap two tokens in the pool
* @param self Swap struct to read from and write to
* @param tokenIndexFrom the token the user wants to sell
* @param tokenIndexTo the token the user wants to buy
* @param dx the amount of tokens the user wants to sell
* @param minDy the min amount the user would like to receive, or revert.
* @return amount of token user received on swap
*/
function swap(
Swap storage self,
uint8 tokenIndexFrom,
uint8 tokenIndexTo,
uint256 dx,
uint256 minDy
) external returns (uint256) {
{
IERC20 tokenFrom = self.pooledTokens[tokenIndexFrom];
require(
dx <= tokenFrom.balanceOf(msg.sender),
"Cannot swap more than you own"
);
// Transfer tokens first to see if a fee was charged on transfer
uint256 beforeBalance = tokenFrom.balanceOf(address(this));
tokenFrom.safeTransferFrom(msg.sender, address(this), dx);
// Use the actual transferred amount for AMM math
dx = tokenFrom.balanceOf(address(this)).sub(beforeBalance);
}
uint256 dy;
uint256 dyFee;
uint256[] memory balances = self.balances;
(dy, dyFee) = _calculateSwap(
self,
tokenIndexFrom,
tokenIndexTo,
dx,
balances
);
require(dy >= minDy, "Swap didn't result in min tokens");
uint256 dyAdminFee = dyFee.mul(self.adminFee).div(FEE_DENOMINATOR).div(
self.tokenPrecisionMultipliers[tokenIndexTo]
);
self.balances[tokenIndexFrom] = balances[tokenIndexFrom].add(dx);
self.balances[tokenIndexTo] = balances[tokenIndexTo].sub(dy).sub(
dyAdminFee
);
self.pooledTokens[tokenIndexTo].safeTransfer(msg.sender, dy);
emit TokenSwap(msg.sender, dx, dy, tokenIndexFrom, tokenIndexTo);
return dy;
}
/**
* @notice Add liquidity to the pool
* @param self Swap struct to read from and write to
* @param amounts the amounts of each token to add, in their native precision
* @param minToMint the minimum LP tokens adding this amount of liquidity
* should mint, otherwise revert. Handy for front-running mitigation
* allowed addresses. If the pool is not in the guarded launch phase, this parameter will be ignored.
* @return amount of LP token user received
*/
function addLiquidity(
Swap storage self,
uint256[] memory amounts,
uint256 minToMint
) external returns (uint256) {
IERC20[] memory pooledTokens = self.pooledTokens;
require(
amounts.length == pooledTokens.length,
"Amounts must match pooled tokens"
);
// current state
ManageLiquidityInfo memory v = ManageLiquidityInfo(
0,
0,
0,
_getAPrecise(self),
self.lpToken,
0,
self.balances,
self.tokenPrecisionMultipliers
);
v.totalSupply = v.lpToken.totalSupply();
if (v.totalSupply != 0) {
v.d0 = getD(_xp(v.balances, v.multipliers), v.preciseA);
}
uint256[] memory newBalances = new uint256[](pooledTokens.length);
for (uint256 i = 0; i < pooledTokens.length; i++) {
require(
v.totalSupply != 0 || amounts[i] > 0,
"Must supply all tokens in pool"
);
// Transfer tokens first to see if a fee was charged on transfer
if (amounts[i] != 0) {
uint256 beforeBalance = pooledTokens[i].balanceOf(
address(this)
);
pooledTokens[i].safeTransferFrom(
msg.sender,
address(this),
amounts[i]
);
// Update the amounts[] with actual transfer amount
amounts[i] = pooledTokens[i].balanceOf(address(this)).sub(
beforeBalance
);
}
newBalances[i] = v.balances[i].add(amounts[i]);
}
// invariant after change
v.d1 = getD(_xp(newBalances, v.multipliers), v.preciseA);
require(v.d1 > v.d0, "D should increase");
// updated to reflect fees and calculate the user's LP tokens
v.d2 = v.d1;
uint256[] memory fees = new uint256[](pooledTokens.length);
if (v.totalSupply != 0) {
uint256 feePerToken = _feePerToken(
self.swapFee,
pooledTokens.length
);
for (uint256 i = 0; i < pooledTokens.length; i++) {
uint256 idealBalance = v.d1.mul(v.balances[i]).div(v.d0);
fees[i] = feePerToken
.mul(idealBalance.difference(newBalances[i]))
.div(FEE_DENOMINATOR);
self.balances[i] = newBalances[i].sub(
fees[i].mul(self.adminFee).div(FEE_DENOMINATOR)
);
newBalances[i] = newBalances[i].sub(fees[i]);
}
v.d2 = getD(_xp(newBalances, v.multipliers), v.preciseA);
} else {
// the initial depositor doesn't pay fees
self.balances = newBalances;
}
uint256 toMint;
if (v.totalSupply == 0) {
toMint = v.d1;
} else {
toMint = v.d2.sub(v.d0).mul(v.totalSupply).div(v.d0);
}
require(toMint >= minToMint, "Couldn't mint min requested");
// mint the user's LP tokens
v.lpToken.mint(msg.sender, toMint);
emit AddLiquidity(
msg.sender,
amounts,
fees,
v.d1,
v.totalSupply.add(toMint)
);
return toMint;
}
/**
* @notice Burn LP tokens to remove liquidity from the pool.
* @dev Liquidity can always be removed, even when the pool is paused.
* @param self Swap struct to read from and write to
* @param amount the amount of LP tokens to burn
* @param minAmounts the minimum amounts of each token in the pool
* acceptable for this burn. Useful as a front-running mitigation
* @return amounts of tokens the user received
*/
function removeLiquidity(
Swap storage self,
uint256 amount,
uint256[] calldata minAmounts
) external returns (uint256[] memory) {
LPToken lpToken = self.lpToken;
IERC20[] memory pooledTokens = self.pooledTokens;
require(amount <= lpToken.balanceOf(msg.sender), ">LP.balanceOf");
require(
minAmounts.length == pooledTokens.length,
"minAmounts must match poolTokens"
);
uint256[] memory balances = self.balances;
uint256 totalSupply = lpToken.totalSupply();
uint256[] memory amounts = _calculateRemoveLiquidity(
balances,
amount,
totalSupply
);
for (uint256 i = 0; i < amounts.length; i++) {
require(amounts[i] >= minAmounts[i], "amounts[i] < minAmounts[i]");
self.balances[i] = balances[i].sub(amounts[i]);
pooledTokens[i].safeTransfer(msg.sender, amounts[i]);
}
lpToken.burnFrom(msg.sender, amount);
emit RemoveLiquidity(msg.sender, amounts, totalSupply.sub(amount));
return amounts;
}
/**
* @notice Remove liquidity from the pool all in one token.
* @param self Swap struct to read from and write to
* @param tokenAmount the amount of the lp tokens to burn
* @param tokenIndex the index of the token you want to receive
* @param minAmount the minimum amount to withdraw, otherwise revert
* @return amount chosen token that user received
*/
function removeLiquidityOneToken(
Swap storage self,
uint256 tokenAmount,
uint8 tokenIndex,
uint256 minAmount
) external returns (uint256) {
LPToken lpToken = self.lpToken;
IERC20[] memory pooledTokens = self.pooledTokens;
require(tokenAmount <= lpToken.balanceOf(msg.sender), ">LP.balanceOf");
require(tokenIndex < pooledTokens.length, "Token not found");
uint256 totalSupply = lpToken.totalSupply();
(uint256 dy, uint256 dyFee) = _calculateWithdrawOneToken(
self,
tokenAmount,
tokenIndex,
totalSupply
);
require(dy >= minAmount, "dy < minAmount");
self.balances[tokenIndex] = self.balances[tokenIndex].sub(
dy.add(dyFee.mul(self.adminFee).div(FEE_DENOMINATOR))
);
lpToken.burnFrom(msg.sender, tokenAmount);
pooledTokens[tokenIndex].safeTransfer(msg.sender, dy);
emit RemoveLiquidityOne(
msg.sender,
tokenAmount,
totalSupply,
tokenIndex,
dy
);
return dy;
}
/**
* @notice Remove liquidity from the pool, weighted differently than the
* pool's current balances.
*
* @param self Swap struct to read from and write to
* @param amounts how much of each token to withdraw
* @param maxBurnAmount the max LP token provider is willing to pay to
* remove liquidity. Useful as a front-running mitigation.
* @return actual amount of LP tokens burned in the withdrawal
*/
function removeLiquidityImbalance(
Swap storage self,
uint256[] memory amounts,
uint256 maxBurnAmount
) public returns (uint256) {
ManageLiquidityInfo memory v = ManageLiquidityInfo(
0,
0,
0,
_getAPrecise(self),
self.lpToken,
0,
self.balances,
self.tokenPrecisionMultipliers
);
v.totalSupply = v.lpToken.totalSupply();
IERC20[] memory pooledTokens = self.pooledTokens;
require(
amounts.length == pooledTokens.length,
"Amounts should match pool tokens"
);
require(
maxBurnAmount <= v.lpToken.balanceOf(msg.sender) &&
maxBurnAmount != 0,
">LP.balanceOf"
);
uint256 feePerToken = _feePerToken(self.swapFee, pooledTokens.length);
uint256[] memory fees = new uint256[](pooledTokens.length);
{
uint256[] memory balances1 = new uint256[](pooledTokens.length);
v.d0 = getD(_xp(v.balances, v.multipliers), v.preciseA);
for (uint256 i = 0; i < pooledTokens.length; i++) {
balances1[i] = v.balances[i].sub(
amounts[i],
"Cannot withdraw more than available"
);
}
v.d1 = getD(_xp(balances1, v.multipliers), v.preciseA);
for (uint256 i = 0; i < pooledTokens.length; i++) {
uint256 idealBalance = v.d1.mul(v.balances[i]).div(v.d0);
uint256 difference = idealBalance.difference(balances1[i]);
fees[i] = feePerToken.mul(difference).div(FEE_DENOMINATOR);
self.balances[i] = balances1[i].sub(
fees[i].mul(self.adminFee).div(FEE_DENOMINATOR)
);
balances1[i] = balances1[i].sub(fees[i]);
}
v.d2 = getD(_xp(balances1, v.multipliers), v.preciseA);
}
uint256 tokenAmount = v.d0.sub(v.d2).mul(v.totalSupply).div(v.d0);
require(tokenAmount != 0, "Burnt amount cannot be zero");
tokenAmount = tokenAmount.add(1);
require(tokenAmount <= maxBurnAmount, "tokenAmount > maxBurnAmount");
v.lpToken.burnFrom(msg.sender, tokenAmount);
for (uint256 i = 0; i < pooledTokens.length; i++) {
pooledTokens[i].safeTransfer(msg.sender, amounts[i]);
}
emit RemoveLiquidityImbalance(
msg.sender,
amounts,
fees,
v.d1,
v.totalSupply.sub(tokenAmount)
);
return tokenAmount;
}
/**
* @notice withdraw all admin fees to a given address
* @param self Swap struct to withdraw fees from
* @param to Address to send the fees to
*/
function withdrawAdminFees(Swap storage self, address to) external {
IERC20[] memory pooledTokens = self.pooledTokens;
for (uint256 i = 0; i < pooledTokens.length; i++) {
IERC20 token = pooledTokens[i];
uint256 balance = token.balanceOf(address(this)).sub(
self.balances[i]
);
if (balance != 0) {
token.safeTransfer(to, balance);
}
}
}
/**
* @notice Sets the admin fee
* @dev adminFee cannot be higher than 100% of the swap fee
* @param self Swap struct to update
* @param newAdminFee new admin fee to be applied on future transactions
*/
function setAdminFee(Swap storage self, uint256 newAdminFee) external {
require(newAdminFee <= MAX_ADMIN_FEE, "Fee is too high");
self.adminFee = newAdminFee;
emit NewAdminFee(newAdminFee);
}
/**
* @notice update the swap fee
* @dev fee cannot be higher than 1% of each swap
* @param self Swap struct to update
* @param newSwapFee new swap fee to be applied on future transactions
*/
function setSwapFee(Swap storage self, uint256 newSwapFee) external {
require(newSwapFee <= MAX_SWAP_FEE, "Fee is too high");
self.swapFee = newSwapFee;
emit NewSwapFee(newSwapFee);
}
/**
* @notice Update the fee collector address
* @param newFeeCollector new address as fee collector
*/
function setFeeCollector(Swap storage self, address newFeeCollector) external {
require(newFeeCollector != address(0), "Address zero is not allowed");
self.feeCollector = newFeeCollector;
emit NewFeeCollector(newFeeCollector);
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "./SwapUtils.sol";
/**
* @title AmplificationUtils library
* @notice A library to calculate and ramp the A parameter of a given `SwapUtils.Swap` struct.
* This library assumes the struct is fully validated.
*/
library AmplificationUtils {
using SafeMath for uint256;
event RampA(
uint256 oldA,
uint256 newA,
uint256 initialTime,
uint256 futureTime
);
event StopRampA(uint256 currentA, uint256 time);
// Constant values used in ramping A calculations
uint256 public constant A_PRECISION = 100;
uint256 public constant MAX_A = 10**6;
uint256 private constant MAX_A_CHANGE = 2;
uint256 private constant MIN_RAMP_TIME = 14 days;
/**
* @notice Return A, the amplification coefficient * n * (n - 1)
* @dev See the StableSwap paper for details
* @param self Swap struct to read from
* @return A parameter
*/
function getA(SwapUtils.Swap storage self) external view returns (uint256) {
return _getAPrecise(self).div(A_PRECISION);
}
/**
* @notice Return A in its raw precision
* @dev See the StableSwap paper for details
* @param self Swap struct to read from
* @return A parameter in its raw precision form
*/
function getAPrecise(SwapUtils.Swap storage self)
external
view
returns (uint256)
{
return _getAPrecise(self);
}
/**
* @notice Return A in its raw precision
* @dev See the StableSwap paper for details
* @param self Swap struct to read from
* @return A parameter in its raw precision form
*/
function _getAPrecise(SwapUtils.Swap storage self)
internal
view
returns (uint256)
{
uint256 t1 = self.futureATime; // time when ramp is finished
uint256 a1 = self.futureA; // final A value when ramp is finished
if (block.timestamp < t1) {
uint256 t0 = self.initialATime; // time when ramp is started
uint256 a0 = self.initialA; // initial A value when ramp is started
if (a1 > a0) {
// a0 + (a1 - a0) * (block.timestamp - t0) / (t1 - t0)
return
a0.add(
a1.sub(a0).mul(block.timestamp.sub(t0)).div(t1.sub(t0))
);
} else {
// a0 - (a0 - a1) * (block.timestamp - t0) / (t1 - t0)
return
a0.sub(
a0.sub(a1).mul(block.timestamp.sub(t0)).div(t1.sub(t0))
);
}
} else {
return a1;
}
}
/**
* @notice Start ramping up or down A parameter towards given futureA_ and futureTime_
* Checks if the change is too rapid, and commits the new A value only when it falls under
* the limit range.
* @param self Swap struct to update
* @param futureA_ the new A to ramp towards
* @param futureTime_ timestamp when the new A should be reached
*/
function rampA(
SwapUtils.Swap storage self,
uint256 futureA_,
uint256 futureTime_
) external {
require(
block.timestamp >= self.initialATime.add(1 days),
"Wait 1 day before starting ramp"
);
require(
futureTime_ >= block.timestamp.add(MIN_RAMP_TIME),
"Insufficient ramp time"
);
require(
futureA_ > 0 && futureA_ < MAX_A,
"futureA_ must be > 0 and < MAX_A"
);
uint256 initialAPrecise = _getAPrecise(self);
uint256 futureAPrecise = futureA_.mul(A_PRECISION);
if (futureAPrecise < initialAPrecise) {
require(
futureAPrecise.mul(MAX_A_CHANGE) >= initialAPrecise,
"futureA_ is too small"
);
} else {
require(
futureAPrecise <= initialAPrecise.mul(MAX_A_CHANGE),
"futureA_ is too large"
);
}
self.initialA = initialAPrecise;
self.futureA = futureAPrecise;
self.initialATime = block.timestamp;
self.futureATime = futureTime_;
emit RampA(
initialAPrecise,
futureAPrecise,
block.timestamp,
futureTime_
);
}
/**
* @notice Stops ramping A immediately. Once this function is called, rampA()
* cannot be called for another 24 hours
* @param self Swap struct to update
*/
function stopRampA(SwapUtils.Swap storage self) external {
require(self.futureATime > block.timestamp, "Ramp is already stopped");
uint256 currentA = _getAPrecise(self);
self.initialA = currentA;
self.futureA = currentA;
self.initialATime = block.timestamp;
self.futureATime = block.timestamp;
emit StopRampA(currentA, block.timestamp);
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @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.
*
* 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 `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
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: MIT
// solhint-disable-next-line compiler-version
pragma solidity >=0.4.24 <0.8.0;
import "../utils/AddressUpgradeable.sol";
/**
* @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
* behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
* external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
* function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
*
* TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
* possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
*
* CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
* that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
*/
abstract contract Initializable {
/**
* @dev Indicates that the contract has been initialized.
*/
bool private _initialized;
/**
* @dev Indicates that the contract is in the process of being initialized.
*/
bool private _initializing;
/**
* @dev Modifier to protect an initializer function from being invoked twice.
*/
modifier initializer() {
require(_initializing || _isConstructor() || !_initialized, "Initializable: contract is already initialized");
bool isTopLevelCall = !_initializing;
if (isTopLevelCall) {
_initializing = true;
_initialized = true;
}
_;
if (isTopLevelCall) {
_initializing = false;
}
}
/// @dev Returns true if and only if the function is running in the constructor
function _isConstructor() private view returns (bool) {
return !AddressUpgradeable.isContract(address(this));
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.2 <0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library AddressUpgradeable {
/**
* @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);
}
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: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../utils/ContextUpgradeable.sol";
import "../proxy/Initializable.sol";
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
function __Ownable_init() internal initializer {
__Context_init_unchained();
__Ownable_init_unchained();
}
function __Ownable_init_unchained() internal initializer {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
uint256[49] private __gap;
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "./ContextUpgradeable.sol";
import "../proxy/Initializable.sol";
/**
* @dev Contract module which allows children to implement an emergency stop
* mechanism that can be triggered by an authorized account.
*
* This module is used through inheritance. It will make available the
* modifiers `whenNotPaused` and `whenPaused`, which can be applied to
* the functions of your contract. Note that they will not be pausable by
* simply including this module, only once the modifiers are put in place.
*/
abstract contract PausableUpgradeable is Initializable, ContextUpgradeable {
/**
* @dev Emitted when the pause is triggered by `account`.
*/
event Paused(address account);
/**
* @dev Emitted when the pause is lifted by `account`.
*/
event Unpaused(address account);
bool private _paused;
/**
* @dev Initializes the contract in unpaused state.
*/
function __Pausable_init() internal initializer {
__Context_init_unchained();
__Pausable_init_unchained();
}
function __Pausable_init_unchained() internal initializer {
_paused = false;
}
/**
* @dev Returns true if the contract is paused, and false otherwise.
*/
function paused() public view virtual returns (bool) {
return _paused;
}
/**
* @dev Modifier to make a function callable only when the contract is not paused.
*
* Requirements:
*
* - The contract must not be paused.
*/
modifier whenNotPaused() {
require(!paused(), "Pausable: paused");
_;
}
/**
* @dev Modifier to make a function callable only when the contract is paused.
*
* Requirements:
*
* - The contract must be paused.
*/
modifier whenPaused() {
require(paused(), "Pausable: not paused");
_;
}
/**
* @dev Triggers stopped state.
*
* Requirements:
*
* - The contract must not be paused.
*/
function _pause() internal virtual whenNotPaused {
_paused = true;
emit Paused(_msgSender());
}
/**
* @dev Returns to normal state.
*
* Requirements:
*
* - The contract must be paused.
*/
function _unpause() internal virtual whenPaused {
_paused = false;
emit Unpaused(_msgSender());
}
uint256[49] private __gap;
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../proxy/Initializable.sol";
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract ContextUpgradeable is Initializable {
function __Context_init() internal initializer {
__Context_init_unchained();
}
function __Context_init_unchained() internal initializer {
}
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
uint256[50] private __gap;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20BurnableUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
import "./interfaces/ISwap.sol";
/**
* @title Liquidity Provider Token
* @notice This token is an ERC20 detailed token with added capability to be minted by the owner.
* It is used to represent user's shares when providing liquidity to swap contracts.
* @dev Only Swap contracts should initialize and own LPToken contracts.
*/
contract LPToken is ERC20BurnableUpgradeable, OwnableUpgradeable {
using SafeMathUpgradeable for uint256;
/**
* @notice Initializes this LPToken contract with the given name and symbol
* @dev The caller of this function will become the owner. A Swap contract should call this
* in its initializer function.
* @param name name of this token
* @param symbol symbol of this token
*/
function initialize(string memory name, string memory symbol)
external
initializer
returns (bool)
{
__Context_init_unchained();
__ERC20_init_unchained(name, symbol);
__Ownable_init_unchained();
return true;
}
/**
* @notice Mints the given amount of LPToken to the recipient.
* @dev only owner can call this mint function
* @param recipient address of account to receive the tokens
* @param amount amount of tokens to mint
*/
function mint(address recipient, uint256 amount) external onlyOwner {
require(amount != 0, "LPToken: cannot mint 0");
_mint(recipient, amount);
}
/**
* @dev Overrides ERC20._beforeTokenTransfer() which get called on every transfers including
* minting and burning. This ensures that Swap.updateUserWithdrawFees are called everytime.
* This assumes the owner is set to a Swap contract's address.
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual override(ERC20Upgradeable) {
super._beforeTokenTransfer(from, to, amount);
require(to != address(this), "LPToken: cannot send to itself");
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "@openzeppelin/contracts/math/SafeMath.sol";
/**
* @title MathUtils library
* @notice A library to be used in conjunction with SafeMath. Contains functions for calculating
* differences between two uint256.
*/
library MathUtils {
/**
* @notice Compares a and b and returns true if the difference between a and b
* is less than 1 or equal to each other.
* @param a uint256 to compare with
* @param b uint256 to compare with
* @return True if the difference between a and b is less than 1 or equal,
* otherwise return false
*/
function within1(uint256 a, uint256 b) internal pure returns (bool) {
return (difference(a, b) <= 1);
}
/**
* @notice Calculates absolute difference between a and b
* @param a uint256 to compare with
* @param b uint256 to compare with
* @return Difference between a and b
*/
function difference(uint256 a, uint256 b) internal pure returns (uint256) {
if (a > b) {
return a - b;
}
return b - a;
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../../utils/ContextUpgradeable.sol";
import "./ERC20Upgradeable.sol";
import "../../proxy/Initializable.sol";
/**
* @dev Extension of {ERC20} that allows token holders to destroy both their own
* tokens and those that they have an allowance for, in a way that can be
* recognized off-chain (via event analysis).
*/
abstract contract ERC20BurnableUpgradeable is Initializable, ContextUpgradeable, ERC20Upgradeable {
function __ERC20Burnable_init() internal initializer {
__Context_init_unchained();
__ERC20Burnable_init_unchained();
}
function __ERC20Burnable_init_unchained() internal initializer {
}
using SafeMathUpgradeable for uint256;
/**
* @dev Destroys `amount` tokens from the caller.
*
* See {ERC20-_burn}.
*/
function burn(uint256 amount) public virtual {
_burn(_msgSender(), amount);
}
/**
* @dev Destroys `amount` tokens from `account`, deducting from the caller's
* allowance.
*
* See {ERC20-_burn} and {ERC20-allowance}.
*
* Requirements:
*
* - the caller must have allowance for ``accounts``'s tokens of at least
* `amount`.
*/
function burnFrom(address account, uint256 amount) public virtual {
uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, "ERC20: burn amount exceeds allowance");
_approve(account, _msgSender(), decreasedAllowance);
_burn(account, amount);
}
uint256[50] private __gap;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "./IAllowlist.sol";
interface ISwap {
// pool data view functions
function getA() external view returns (uint256);
function getAllowlist() external view returns (IAllowlist);
function getToken(uint8 index) external view returns (IERC20);
function getTokenIndex(address tokenAddress) external view returns (uint8);
function getTokenBalance(uint8 index) external view returns (uint256);
function getVirtualPrice() external view returns (uint256);
function isGuarded() external view returns (bool);
function swapStorage()
external
view
returns (
uint256,
uint256,
uint256,
uint256,
uint256,
uint256,
address
);
// min return calculation functions
function calculateSwap(
uint8 tokenIndexFrom,
uint8 tokenIndexTo,
uint256 dx
) external view returns (uint256);
function calculateTokenAmount(uint256[] calldata amounts, bool deposit)
external
view
returns (uint256);
function calculateRemoveLiquidity(uint256 amount)
external
view
returns (uint256[] memory);
function calculateRemoveLiquidityOneToken(
uint256 tokenAmount,
uint8 tokenIndex
) external view returns (uint256 availableTokenAmount);
// state modifying functions
function initialize(
IERC20[] memory pooledTokens,
uint8[] memory decimals,
string memory lpTokenName,
string memory lpTokenSymbol,
uint256 a,
uint256 fee,
uint256 adminFee,
address lpTokenTargetAddress
) external;
function swap(
uint8 tokenIndexFrom,
uint8 tokenIndexTo,
uint256 dx,
uint256 minDy,
uint256 deadline
) external returns (uint256);
function addLiquidity(
uint256[] calldata amounts,
uint256 minToMint,
uint256 deadline
) external returns (uint256);
function removeLiquidity(
uint256 amount,
uint256[] calldata minAmounts,
uint256 deadline
) external returns (uint256[] memory);
function removeLiquidityOneToken(
uint256 tokenAmount,
uint8 tokenIndex,
uint256 minAmount,
uint256 deadline
) external returns (uint256);
function removeLiquidityImbalance(
uint256[] calldata amounts,
uint256 maxBurnAmount,
uint256 deadline
) external returns (uint256);
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../../utils/ContextUpgradeable.sol";
import "./IERC20Upgradeable.sol";
import "../../math/SafeMathUpgradeable.sol";
import "../../proxy/Initializable.sol";
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin guidelines: functions revert instead
* of returning `false` on failure. This behavior is nonetheless conventional
* and does not conflict with the expectations of ERC20 applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20Upgradeable is Initializable, ContextUpgradeable, IERC20Upgradeable {
using SafeMathUpgradeable for uint256;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
/**
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with
* a default value of 18.
*
* To select a different value for {decimals}, use {_setupDecimals}.
*
* All three of these values are immutable: they can only be set once during
* construction.
*/
function __ERC20_init(string memory name_, string memory symbol_) internal initializer {
__Context_init_unchained();
__ERC20_init_unchained(name_, symbol_);
}
function __ERC20_init_unchained(string memory name_, string memory symbol_) internal initializer {
_name = name_;
_symbol = symbol_;
_decimals = 18;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5,05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
* called.
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view virtual returns (uint8) {
return _decimals;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* Requirements:
*
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for ``sender``'s tokens of at least
* `amount`.
*/
function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
return true;
}
/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(address sender, address recipient, uint256 amount) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `to` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(address owner, address spender, uint256 amount) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Sets {decimals} to a value other than the default one of 18.
*
* WARNING: This function should only be called from the constructor. Most
* applications that interact with token contracts will not expect
* {decimals} to ever change, and may work incorrectly if it does.
*/
function _setupDecimals(uint8 decimals_) internal virtual {
_decimals = decimals_;
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be to transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
uint256[44] private __gap;
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20Upgradeable {
/**
* @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.
*
* 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 `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
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/
library SafeMathUpgradeable {
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
/**
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b > a) return (false, 0);
return (true, a - b);
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) return (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b == 0) return (false, 0);
return (true, a / b);
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b == 0) return (false, 0);
return (true, a % b);
}
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
require(b <= a, "SafeMath: subtraction overflow");
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) return 0;
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
require(b > 0, "SafeMath: division by zero");
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
require(b > 0, "SafeMath: modulo by zero");
return a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
return a - b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
* division by zero. The result is rounded towards zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryDiv}.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
return a % b;
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../../utils/Context.sol";
import "./IERC20.sol";
import "../../math/SafeMath.sol";
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin guidelines: functions revert instead
* of returning `false` on failure. This behavior is nonetheless conventional
* and does not conflict with the expectations of ERC20 applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20 {
using SafeMath for uint256;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
/**
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with
* a default value of 18.
*
* To select a different value for {decimals}, use {_setupDecimals}.
*
* All three of these values are immutable: they can only be set once during
* construction.
*/
constructor (string memory name_, string memory symbol_) public {
_name = name_;
_symbol = symbol_;
_decimals = 18;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5,05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
* called.
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view virtual returns (uint8) {
return _decimals;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* Requirements:
*
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for ``sender``'s tokens of at least
* `amount`.
*/
function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
return true;
}
/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(address sender, address recipient, uint256 amount) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `to` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(address owner, address spender, uint256 amount) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Sets {decimals} to a value other than the default one of 18.
*
* WARNING: This function should only be called from the constructor. Most
* applications that interact with token contracts will not expect
* {decimals} to ever change, and may work incorrectly if it does.
*/
function _setupDecimals(uint8 decimals_) internal virtual {
_decimals = decimals_;
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be to transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
interface IAllowlist {
function getPoolAccountLimit(address poolAddress)
external
view
returns (uint256);
function getPoolCap(address poolAddress) external view returns (uint256);
function verifyAddress(address account, bytes32[] calldata merkleProof)
external
returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}