Contract Source Code:
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (interfaces/IERC4626.sol)
pragma solidity ^0.8.0;
import "../token/ERC20/IERC20.sol";
import "../token/ERC20/extensions/IERC20Metadata.sol";
/**
* @dev Interface of the ERC4626 "Tokenized Vault Standard", as defined in
* https://eips.ethereum.org/EIPS/eip-4626[ERC-4626].
*
* _Available since v4.7._
*/
interface IERC4626 is IERC20, IERC20Metadata {
event Deposit(address indexed sender, address indexed owner, uint256 assets, uint256 shares);
event Withdraw(
address indexed sender,
address indexed receiver,
address indexed owner,
uint256 assets,
uint256 shares
);
/**
* @dev Returns the address of the underlying token used for the Vault for accounting, depositing, and withdrawing.
*
* - MUST be an ERC-20 token contract.
* - MUST NOT revert.
*/
function asset() external view returns (address assetTokenAddress);
/**
* @dev Returns the total amount of the underlying asset that is “managed” by Vault.
*
* - SHOULD include any compounding that occurs from yield.
* - MUST be inclusive of any fees that are charged against assets in the Vault.
* - MUST NOT revert.
*/
function totalAssets() external view returns (uint256 totalManagedAssets);
/**
* @dev Returns the amount of shares that the Vault would exchange for the amount of assets provided, in an ideal
* scenario where all the conditions are met.
*
* - MUST NOT be inclusive of any fees that are charged against assets in the Vault.
* - MUST NOT show any variations depending on the caller.
* - MUST NOT reflect slippage or other on-chain conditions, when performing the actual exchange.
* - MUST NOT revert.
*
* NOTE: This calculation MAY NOT reflect the “per-user” price-per-share, and instead should reflect the
* “average-user’s” price-per-share, meaning what the average user should expect to see when exchanging to and
* from.
*/
function convertToShares(uint256 assets) external view returns (uint256 shares);
/**
* @dev Returns the amount of assets that the Vault would exchange for the amount of shares provided, in an ideal
* scenario where all the conditions are met.
*
* - MUST NOT be inclusive of any fees that are charged against assets in the Vault.
* - MUST NOT show any variations depending on the caller.
* - MUST NOT reflect slippage or other on-chain conditions, when performing the actual exchange.
* - MUST NOT revert.
*
* NOTE: This calculation MAY NOT reflect the “per-user” price-per-share, and instead should reflect the
* “average-user’s” price-per-share, meaning what the average user should expect to see when exchanging to and
* from.
*/
function convertToAssets(uint256 shares) external view returns (uint256 assets);
/**
* @dev Returns the maximum amount of the underlying asset that can be deposited into the Vault for the receiver,
* through a deposit call.
*
* - MUST return a limited value if receiver is subject to some deposit limit.
* - MUST return 2 ** 256 - 1 if there is no limit on the maximum amount of assets that may be deposited.
* - MUST NOT revert.
*/
function maxDeposit(address receiver) external view returns (uint256 maxAssets);
/**
* @dev Allows an on-chain or off-chain user to simulate the effects of their deposit at the current block, given
* current on-chain conditions.
*
* - MUST return as close to and no more than the exact amount of Vault shares that would be minted in a deposit
* call in the same transaction. I.e. deposit should return the same or more shares as previewDeposit if called
* in the same transaction.
* - MUST NOT account for deposit limits like those returned from maxDeposit and should always act as though the
* deposit would be accepted, regardless if the user has enough tokens approved, etc.
* - MUST be inclusive of deposit fees. Integrators should be aware of the existence of deposit fees.
* - MUST NOT revert.
*
* NOTE: any unfavorable discrepancy between convertToShares and previewDeposit SHOULD be considered slippage in
* share price or some other type of condition, meaning the depositor will lose assets by depositing.
*/
function previewDeposit(uint256 assets) external view returns (uint256 shares);
/**
* @dev Mints shares Vault shares to receiver by depositing exactly amount of underlying tokens.
*
* - MUST emit the Deposit event.
* - MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the
* deposit execution, and are accounted for during deposit.
* - MUST revert if all of assets cannot be deposited (due to deposit limit being reached, slippage, the user not
* approving enough underlying tokens to the Vault contract, etc).
*
* NOTE: most implementations will require pre-approval of the Vault with the Vault’s underlying asset token.
*/
function deposit(uint256 assets, address receiver) external returns (uint256 shares);
/**
* @dev Returns the maximum amount of the Vault shares that can be minted for the receiver, through a mint call.
* - MUST return a limited value if receiver is subject to some mint limit.
* - MUST return 2 ** 256 - 1 if there is no limit on the maximum amount of shares that may be minted.
* - MUST NOT revert.
*/
function maxMint(address receiver) external view returns (uint256 maxShares);
/**
* @dev Allows an on-chain or off-chain user to simulate the effects of their mint at the current block, given
* current on-chain conditions.
*
* - MUST return as close to and no fewer than the exact amount of assets that would be deposited in a mint call
* in the same transaction. I.e. mint should return the same or fewer assets as previewMint if called in the
* same transaction.
* - MUST NOT account for mint limits like those returned from maxMint and should always act as though the mint
* would be accepted, regardless if the user has enough tokens approved, etc.
* - MUST be inclusive of deposit fees. Integrators should be aware of the existence of deposit fees.
* - MUST NOT revert.
*
* NOTE: any unfavorable discrepancy between convertToAssets and previewMint SHOULD be considered slippage in
* share price or some other type of condition, meaning the depositor will lose assets by minting.
*/
function previewMint(uint256 shares) external view returns (uint256 assets);
/**
* @dev Mints exactly shares Vault shares to receiver by depositing amount of underlying tokens.
*
* - MUST emit the Deposit event.
* - MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the mint
* execution, and are accounted for during mint.
* - MUST revert if all of shares cannot be minted (due to deposit limit being reached, slippage, the user not
* approving enough underlying tokens to the Vault contract, etc).
*
* NOTE: most implementations will require pre-approval of the Vault with the Vault’s underlying asset token.
*/
function mint(uint256 shares, address receiver) external returns (uint256 assets);
/**
* @dev Returns the maximum amount of the underlying asset that can be withdrawn from the owner balance in the
* Vault, through a withdraw call.
*
* - MUST return a limited value if owner is subject to some withdrawal limit or timelock.
* - MUST NOT revert.
*/
function maxWithdraw(address owner) external view returns (uint256 maxAssets);
/**
* @dev Allows an on-chain or off-chain user to simulate the effects of their withdrawal at the current block,
* given current on-chain conditions.
*
* - MUST return as close to and no fewer than the exact amount of Vault shares that would be burned in a withdraw
* call in the same transaction. I.e. withdraw should return the same or fewer shares as previewWithdraw if
* called
* in the same transaction.
* - MUST NOT account for withdrawal limits like those returned from maxWithdraw and should always act as though
* the withdrawal would be accepted, regardless if the user has enough shares, etc.
* - MUST be inclusive of withdrawal fees. Integrators should be aware of the existence of withdrawal fees.
* - MUST NOT revert.
*
* NOTE: any unfavorable discrepancy between convertToShares and previewWithdraw SHOULD be considered slippage in
* share price or some other type of condition, meaning the depositor will lose assets by depositing.
*/
function previewWithdraw(uint256 assets) external view returns (uint256 shares);
/**
* @dev Burns shares from owner and sends exactly assets of underlying tokens to receiver.
*
* - MUST emit the Withdraw event.
* - MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the
* withdraw execution, and are accounted for during withdraw.
* - MUST revert if all of assets cannot be withdrawn (due to withdrawal limit being reached, slippage, the owner
* not having enough shares, etc).
*
* Note that some implementations will require pre-requesting to the Vault before a withdrawal may be performed.
* Those methods should be performed separately.
*/
function withdraw(uint256 assets, address receiver, address owner) external returns (uint256 shares);
/**
* @dev Returns the maximum amount of Vault shares that can be redeemed from the owner balance in the Vault,
* through a redeem call.
*
* - MUST return a limited value if owner is subject to some withdrawal limit or timelock.
* - MUST return balanceOf(owner) if owner is not subject to any withdrawal limit or timelock.
* - MUST NOT revert.
*/
function maxRedeem(address owner) external view returns (uint256 maxShares);
/**
* @dev Allows an on-chain or off-chain user to simulate the effects of their redeemption at the current block,
* given current on-chain conditions.
*
* - MUST return as close to and no more than the exact amount of assets that would be withdrawn in a redeem call
* in the same transaction. I.e. redeem should return the same or more assets as previewRedeem if called in the
* same transaction.
* - MUST NOT account for redemption limits like those returned from maxRedeem and should always act as though the
* redemption would be accepted, regardless if the user has enough shares, etc.
* - MUST be inclusive of withdrawal fees. Integrators should be aware of the existence of withdrawal fees.
* - MUST NOT revert.
*
* NOTE: any unfavorable discrepancy between convertToAssets and previewRedeem SHOULD be considered slippage in
* share price or some other type of condition, meaning the depositor will lose assets by redeeming.
*/
function previewRedeem(uint256 shares) external view returns (uint256 assets);
/**
* @dev Burns exactly shares from owner and sends assets of underlying tokens to receiver.
*
* - MUST emit the Withdraw event.
* - MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the
* redeem execution, and are accounted for during redeem.
* - MUST revert if all of shares cannot be redeemed (due to withdrawal limit being reached, slippage, the owner
* not having enough shares, etc).
*
* NOTE: some implementations will require pre-requesting to the Vault before a withdrawal may be performed.
* Those methods should be performed separately.
*/
function redeem(uint256 shares, address receiver, address owner) external returns (uint256 assets);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/ERC20.sol)
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.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.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* The default value of {decimals} is 18. To change this, you should override
* this function so it returns a different value.
*
* We have followed general OpenZeppelin Contracts guidelines: functions revert
* instead 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, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
/**
* @dev Sets the values for {name} and {symbol}.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override 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 default value returned by this function, unless
* it's overridden.
*
* 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 override returns (uint8) {
return 18;
}
/**
* @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:
*
* - `to` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address to, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_transfer(owner, to, 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}.
*
* NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
* `transferFrom`. This is semantically equivalent to an infinite approval.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_approve(owner, 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}.
*
* NOTE: Does not update the allowance if the current allowance
* is the maximum `uint256`.
*
* Requirements:
*
* - `from` and `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
* - the caller must have allowance for ``from``'s tokens of at least
* `amount`.
*/
function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
address spender = _msgSender();
_spendAllowance(from, spender, amount);
_transfer(from, to, amount);
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) {
address owner = _msgSender();
_approve(owner, spender, allowance(owner, spender) + 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) {
address owner = _msgSender();
uint256 currentAllowance = allowance(owner, spender);
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `from` to `to`.
*
* This 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:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
*/
function _transfer(address from, address to, uint256 amount) internal virtual {
require(from != address(0), "ERC20: transfer from the zero address");
require(to != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(from, to, amount);
uint256 fromBalance = _balances[from];
require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[from] = fromBalance - amount;
// Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
// decrementing then incrementing.
_balances[to] += amount;
}
emit Transfer(from, to, amount);
_afterTokenTransfer(from, to, 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:
*
* - `account` 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 += amount;
unchecked {
// Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
_balances[account] += amount;
}
emit Transfer(address(0), account, amount);
_afterTokenTransfer(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);
uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
// Overflow not possible: amount <= accountBalance <= totalSupply.
_totalSupply -= amount;
}
emit Transfer(account, address(0), amount);
_afterTokenTransfer(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 Updates `owner` s allowance for `spender` based on spent `amount`.
*
* Does not update the allowance amount in case of infinite allowance.
* Revert if not enough allowance is available.
*
* Might emit an {Approval} event.
*/
function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
uint256 currentAllowance = allowance(owner, spender);
if (currentAllowance != type(uint256).max) {
require(currentAllowance >= amount, "ERC20: insufficient allowance");
unchecked {
_approve(owner, spender, currentAllowance - amount);
}
}
}
/**
* @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 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 {}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been 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 _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/ERC4626.sol)
pragma solidity ^0.8.0;
import "../ERC20.sol";
import "../utils/SafeERC20.sol";
import "../../../interfaces/IERC4626.sol";
import "../../../utils/math/Math.sol";
/**
* @dev Implementation of the ERC4626 "Tokenized Vault Standard" as defined in
* https://eips.ethereum.org/EIPS/eip-4626[EIP-4626].
*
* This extension allows the minting and burning of "shares" (represented using the ERC20 inheritance) in exchange for
* underlying "assets" through standardized {deposit}, {mint}, {redeem} and {burn} workflows. This contract extends
* the ERC20 standard. Any additional extensions included along it would affect the "shares" token represented by this
* contract and not the "assets" token which is an independent contract.
*
* [CAUTION]
* ====
* In empty (or nearly empty) ERC-4626 vaults, deposits are at high risk of being stolen through frontrunning
* with a "donation" to the vault that inflates the price of a share. This is variously known as a donation or inflation
* attack and is essentially a problem of slippage. Vault deployers can protect against this attack by making an initial
* deposit of a non-trivial amount of the asset, such that price manipulation becomes infeasible. Withdrawals may
* similarly be affected by slippage. Users can protect against this attack as well as unexpected slippage in general by
* verifying the amount received is as expected, using a wrapper that performs these checks such as
* https://github.com/fei-protocol/ERC4626#erc4626router-and-base[ERC4626Router].
*
* Since v4.9, this implementation uses virtual assets and shares to mitigate that risk. The `_decimalsOffset()`
* corresponds to an offset in the decimal representation between the underlying asset's decimals and the vault
* decimals. This offset also determines the rate of virtual shares to virtual assets in the vault, which itself
* determines the initial exchange rate. While not fully preventing the attack, analysis shows that the default offset
* (0) makes it non-profitable, as a result of the value being captured by the virtual shares (out of the attacker's
* donation) matching the attacker's expected gains. With a larger offset, the attack becomes orders of magnitude more
* expensive than it is profitable. More details about the underlying math can be found
* xref:erc4626.adoc#inflation-attack[here].
*
* The drawback of this approach is that the virtual shares do capture (a very small) part of the value being accrued
* to the vault. Also, if the vault experiences losses, the users try to exit the vault, the virtual shares and assets
* will cause the first user to exit to experience reduced losses in detriment to the last users that will experience
* bigger losses. Developers willing to revert back to the pre-v4.9 behavior just need to override the
* `_convertToShares` and `_convertToAssets` functions.
*
* To learn more, check out our xref:ROOT:erc4626.adoc[ERC-4626 guide].
* ====
*
* _Available since v4.7._
*/
abstract contract ERC4626 is ERC20, IERC4626 {
using Math for uint256;
IERC20 private immutable _asset;
uint8 private immutable _underlyingDecimals;
/**
* @dev Set the underlying asset contract. This must be an ERC20-compatible contract (ERC20 or ERC777).
*/
constructor(IERC20 asset_) {
(bool success, uint8 assetDecimals) = _tryGetAssetDecimals(asset_);
_underlyingDecimals = success ? assetDecimals : 18;
_asset = asset_;
}
/**
* @dev Attempts to fetch the asset decimals. A return value of false indicates that the attempt failed in some way.
*/
function _tryGetAssetDecimals(IERC20 asset_) private view returns (bool, uint8) {
(bool success, bytes memory encodedDecimals) = address(asset_).staticcall(
abi.encodeWithSelector(IERC20Metadata.decimals.selector)
);
if (success && encodedDecimals.length >= 32) {
uint256 returnedDecimals = abi.decode(encodedDecimals, (uint256));
if (returnedDecimals <= type(uint8).max) {
return (true, uint8(returnedDecimals));
}
}
return (false, 0);
}
/**
* @dev Decimals are computed by adding the decimal offset on top of the underlying asset's decimals. This
* "original" value is cached during construction of the vault contract. If this read operation fails (e.g., the
* asset has not been created yet), a default of 18 is used to represent the underlying asset's decimals.
*
* See {IERC20Metadata-decimals}.
*/
function decimals() public view virtual override(IERC20Metadata, ERC20) returns (uint8) {
return _underlyingDecimals + _decimalsOffset();
}
/** @dev See {IERC4626-asset}. */
function asset() public view virtual override returns (address) {
return address(_asset);
}
/** @dev See {IERC4626-totalAssets}. */
function totalAssets() public view virtual override returns (uint256) {
return _asset.balanceOf(address(this));
}
/** @dev See {IERC4626-convertToShares}. */
function convertToShares(uint256 assets) public view virtual override returns (uint256) {
return _convertToShares(assets, Math.Rounding.Down);
}
/** @dev See {IERC4626-convertToAssets}. */
function convertToAssets(uint256 shares) public view virtual override returns (uint256) {
return _convertToAssets(shares, Math.Rounding.Down);
}
/** @dev See {IERC4626-maxDeposit}. */
function maxDeposit(address) public view virtual override returns (uint256) {
return type(uint256).max;
}
/** @dev See {IERC4626-maxMint}. */
function maxMint(address) public view virtual override returns (uint256) {
return type(uint256).max;
}
/** @dev See {IERC4626-maxWithdraw}. */
function maxWithdraw(address owner) public view virtual override returns (uint256) {
return _convertToAssets(balanceOf(owner), Math.Rounding.Down);
}
/** @dev See {IERC4626-maxRedeem}. */
function maxRedeem(address owner) public view virtual override returns (uint256) {
return balanceOf(owner);
}
/** @dev See {IERC4626-previewDeposit}. */
function previewDeposit(uint256 assets) public view virtual override returns (uint256) {
return _convertToShares(assets, Math.Rounding.Down);
}
/** @dev See {IERC4626-previewMint}. */
function previewMint(uint256 shares) public view virtual override returns (uint256) {
return _convertToAssets(shares, Math.Rounding.Up);
}
/** @dev See {IERC4626-previewWithdraw}. */
function previewWithdraw(uint256 assets) public view virtual override returns (uint256) {
return _convertToShares(assets, Math.Rounding.Up);
}
/** @dev See {IERC4626-previewRedeem}. */
function previewRedeem(uint256 shares) public view virtual override returns (uint256) {
return _convertToAssets(shares, Math.Rounding.Down);
}
/** @dev See {IERC4626-deposit}. */
function deposit(uint256 assets, address receiver) public virtual override returns (uint256) {
require(assets <= maxDeposit(receiver), "ERC4626: deposit more than max");
uint256 shares = previewDeposit(assets);
_deposit(_msgSender(), receiver, assets, shares);
return shares;
}
/** @dev See {IERC4626-mint}.
*
* As opposed to {deposit}, minting is allowed even if the vault is in a state where the price of a share is zero.
* In this case, the shares will be minted without requiring any assets to be deposited.
*/
function mint(uint256 shares, address receiver) public virtual override returns (uint256) {
require(shares <= maxMint(receiver), "ERC4626: mint more than max");
uint256 assets = previewMint(shares);
_deposit(_msgSender(), receiver, assets, shares);
return assets;
}
/** @dev See {IERC4626-withdraw}. */
function withdraw(uint256 assets, address receiver, address owner) public virtual override returns (uint256) {
require(assets <= maxWithdraw(owner), "ERC4626: withdraw more than max");
uint256 shares = previewWithdraw(assets);
_withdraw(_msgSender(), receiver, owner, assets, shares);
return shares;
}
/** @dev See {IERC4626-redeem}. */
function redeem(uint256 shares, address receiver, address owner) public virtual override returns (uint256) {
require(shares <= maxRedeem(owner), "ERC4626: redeem more than max");
uint256 assets = previewRedeem(shares);
_withdraw(_msgSender(), receiver, owner, assets, shares);
return assets;
}
/**
* @dev Internal conversion function (from assets to shares) with support for rounding direction.
*/
function _convertToShares(uint256 assets, Math.Rounding rounding) internal view virtual returns (uint256) {
return assets.mulDiv(totalSupply() + 10 ** _decimalsOffset(), totalAssets() + 1, rounding);
}
/**
* @dev Internal conversion function (from shares to assets) with support for rounding direction.
*/
function _convertToAssets(uint256 shares, Math.Rounding rounding) internal view virtual returns (uint256) {
return shares.mulDiv(totalAssets() + 1, totalSupply() + 10 ** _decimalsOffset(), rounding);
}
/**
* @dev Deposit/mint common workflow.
*/
function _deposit(address caller, address receiver, uint256 assets, uint256 shares) internal virtual {
// If _asset is ERC777, `transferFrom` can trigger a reentrancy BEFORE the transfer happens through the
// `tokensToSend` hook. On the other hand, the `tokenReceived` hook, that is triggered after the transfer,
// calls the vault, which is assumed not malicious.
//
// Conclusion: we need to do the transfer before we mint so that any reentrancy would happen before the
// assets are transferred and before the shares are minted, which is a valid state.
// slither-disable-next-line reentrancy-no-eth
SafeERC20.safeTransferFrom(_asset, caller, address(this), assets);
_mint(receiver, shares);
emit Deposit(caller, receiver, assets, shares);
}
/**
* @dev Withdraw/redeem common workflow.
*/
function _withdraw(
address caller,
address receiver,
address owner,
uint256 assets,
uint256 shares
) internal virtual {
if (caller != owner) {
_spendAllowance(owner, caller, shares);
}
// If _asset is ERC777, `transfer` can trigger a reentrancy AFTER the transfer happens through the
// `tokensReceived` hook. On the other hand, the `tokensToSend` hook, that is triggered before the transfer,
// calls the vault, which is assumed not malicious.
//
// Conclusion: we need to do the transfer after the burn so that any reentrancy would happen after the
// shares are burned and after the assets are transferred, which is a valid state.
_burn(owner, shares);
SafeERC20.safeTransfer(_asset, receiver, assets);
emit Withdraw(caller, receiver, owner, assets, shares);
}
function _decimalsOffset() internal view virtual returns (uint8) {
return 0;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/
interface IERC20Metadata is IERC20 {
/**
* @dev Returns the name of the token.
*/
function name() external view returns (string memory);
/**
* @dev Returns the symbol of the token.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the decimals places of the token.
*/
function decimals() external view returns (uint8);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.4) (token/ERC20/extensions/IERC20Permit.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
* https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
*
* Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
* presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
* need to send a transaction, and thus is not required to hold Ether at all.
*
* ==== Security Considerations
*
* There are two important considerations concerning the use of `permit`. The first is that a valid permit signature
* expresses an allowance, and it should not be assumed to convey additional meaning. In particular, it should not be
* considered as an intention to spend the allowance in any specific way. The second is that because permits have
* built-in replay protection and can be submitted by anyone, they can be frontrun. A protocol that uses permits should
* take this into consideration and allow a `permit` call to fail. Combining these two aspects, a pattern that may be
* generally recommended is:
*
* ```solidity
* function doThingWithPermit(..., uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
* try token.permit(msg.sender, address(this), value, deadline, v, r, s) {} catch {}
* doThing(..., value);
* }
*
* function doThing(..., uint256 value) public {
* token.safeTransferFrom(msg.sender, address(this), value);
* ...
* }
* ```
*
* Observe that: 1) `msg.sender` is used as the owner, leaving no ambiguity as to the signer intent, and 2) the use of
* `try/catch` allows the permit to fail and makes the code tolerant to frontrunning. (See also
* {SafeERC20-safeTransferFrom}).
*
* Additionally, note that smart contract wallets (such as Argent or Safe) are not able to produce permit signatures, so
* contracts should have entry points that don't rely on permit.
*/
interface IERC20Permit {
/**
* @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
* given ``owner``'s signed approval.
*
* IMPORTANT: The same issues {IERC20-approve} has related to transaction
* ordering also apply here.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `deadline` must be a timestamp in the future.
* - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
* over the EIP712-formatted function arguments.
* - the signature must use ``owner``'s current nonce (see {nonces}).
*
* For more information on the signature format, see the
* https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
* section].
*
* CAUTION: See Security Considerations above.
*/
function permit(
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) external;
/**
* @dev Returns the current nonce for `owner`. This value must be
* included whenever a signature is generated for {permit}.
*
* Every successful call to {permit} increases ``owner``'s nonce by one. This
* prevents a signature from being used multiple times.
*/
function nonces(address owner) external view returns (uint256);
/**
* @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
*/
// solhint-disable-next-line func-name-mixedcase
function DOMAIN_SEPARATOR() external view returns (bytes32);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `from` to `to` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(address from, address to, uint256 amount) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.3) (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../extensions/IERC20Permit.sol";
import "../../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using Address for address;
/**
* @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
* non-reverting calls are assumed to be successful.
*/
function safeTransfer(IERC20 token, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
/**
* @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
* calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
*/
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(IERC20 token, address spender, uint256 value) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
require(
(value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
/**
* @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
* non-reverting calls are assumed to be successful.
*/
function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 oldAllowance = token.allowance(address(this), spender);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
}
/**
* @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
* non-reverting calls are assumed to be successful.
*/
function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
}
}
/**
* @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
* non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
* to be set to zero before setting it to a non-zero value, such as USDT.
*/
function forceApprove(IERC20 token, address spender, uint256 value) internal {
bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);
if (!_callOptionalReturnBool(token, approvalCall)) {
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
_callOptionalReturn(token, approvalCall);
}
}
/**
* @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
* Revert on invalid signature.
*/
function safePermit(
IERC20Permit token,
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
) internal {
uint256 nonceBefore = token.nonces(owner);
token.permit(owner, spender, value, deadline, v, r, s);
uint256 nonceAfter = token.nonces(owner);
require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*
* This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
*/
function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
// and not revert is the subcall reverts.
(bool success, bytes memory returndata) = address(token).call(data);
return
success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)
pragma solidity ^0.8.1;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
*
* Furthermore, `isContract` will also return true if the target contract within
* the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
* which only has an effect at the end of a transaction.
* ====
*
* [IMPORTANT]
* ====
* You shouldn't rely on `isContract` to protect against flash loan attacks!
*
* Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
* like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
* constructor.
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize/address.code.length, which returns 0
// for contracts in construction, since the code is only stored at the end
// of the constructor execution.
return account.code.length > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://consensys.net/diligence/blog/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/v0.8.0/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{value: amount}("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain `call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value,
string memory errorMessage
) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
(bool success, bytes memory returndata) = target.call{value: value}(data);
return verifyCallResultFromTarget(target, success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResultFromTarget(target, success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResultFromTarget(target, success, returndata, errorMessage);
}
/**
* @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
* the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
*
* _Available since v4.8._
*/
function verifyCallResultFromTarget(
address target,
bool success,
bytes memory returndata,
string memory errorMessage
) internal view returns (bytes memory) {
if (success) {
if (returndata.length == 0) {
// only check isContract if the call was successful and the return data is empty
// otherwise we already know that it was a contract
require(isContract(target), "Address: call to non-contract");
}
return returndata;
} else {
_revert(returndata, errorMessage);
}
}
/**
* @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason or using the provided one.
*
* _Available since v4.3._
*/
function verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) internal pure returns (bytes memory) {
if (success) {
return returndata;
} else {
_revert(returndata, errorMessage);
}
}
function _revert(bytes memory returndata, string memory errorMessage) private pure {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
/// @solidity memory-safe-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.4) (utils/Context.sol)
pragma solidity ^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 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) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
function _contextSuffixLength() internal view virtual returns (uint256) {
return 0;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)
pragma solidity ^0.8.0;
/**
* @dev Standard math utilities missing in the Solidity language.
*/
library Math {
enum Rounding {
Down, // Toward negative infinity
Up, // Toward infinity
Zero // Toward zero
}
/**
* @dev Returns the largest of two numbers.
*/
function max(uint256 a, uint256 b) internal pure returns (uint256) {
return a > b ? a : b;
}
/**
* @dev Returns the smallest of two numbers.
*/
function min(uint256 a, uint256 b) internal pure returns (uint256) {
return a < b ? a : b;
}
/**
* @dev Returns the average of two numbers. The result is rounded towards
* zero.
*/
function average(uint256 a, uint256 b) internal pure returns (uint256) {
// (a + b) / 2 can overflow.
return (a & b) + (a ^ b) / 2;
}
/**
* @dev Returns the ceiling of the division of two numbers.
*
* This differs from standard division with `/` in that it rounds up instead
* of rounding down.
*/
function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
// (a + b - 1) / b can overflow on addition, so we distribute.
return a == 0 ? 0 : (a - 1) / b + 1;
}
/**
* @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
* @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
* with further edits by Uniswap Labs also under MIT license.
*/
function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
unchecked {
// 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
// use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
// variables such that product = prod1 * 2^256 + prod0.
uint256 prod0; // Least significant 256 bits of the product
uint256 prod1; // Most significant 256 bits of the product
assembly {
let mm := mulmod(x, y, not(0))
prod0 := mul(x, y)
prod1 := sub(sub(mm, prod0), lt(mm, prod0))
}
// Handle non-overflow cases, 256 by 256 division.
if (prod1 == 0) {
// Solidity will revert if denominator == 0, unlike the div opcode on its own.
// The surrounding unchecked block does not change this fact.
// See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
return prod0 / denominator;
}
// Make sure the result is less than 2^256. Also prevents denominator == 0.
require(denominator > prod1, "Math: mulDiv overflow");
///////////////////////////////////////////////
// 512 by 256 division.
///////////////////////////////////////////////
// Make division exact by subtracting the remainder from [prod1 prod0].
uint256 remainder;
assembly {
// Compute remainder using mulmod.
remainder := mulmod(x, y, denominator)
// Subtract 256 bit number from 512 bit number.
prod1 := sub(prod1, gt(remainder, prod0))
prod0 := sub(prod0, remainder)
}
// Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
// See https://cs.stackexchange.com/q/138556/92363.
// Does not overflow because the denominator cannot be zero at this stage in the function.
uint256 twos = denominator & (~denominator + 1);
assembly {
// Divide denominator by twos.
denominator := div(denominator, twos)
// Divide [prod1 prod0] by twos.
prod0 := div(prod0, twos)
// Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
twos := add(div(sub(0, twos), twos), 1)
}
// Shift in bits from prod1 into prod0.
prod0 |= prod1 * twos;
// Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
// that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
// four bits. That is, denominator * inv = 1 mod 2^4.
uint256 inverse = (3 * denominator) ^ 2;
// Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
// in modular arithmetic, doubling the correct bits in each step.
inverse *= 2 - denominator * inverse; // inverse mod 2^8
inverse *= 2 - denominator * inverse; // inverse mod 2^16
inverse *= 2 - denominator * inverse; // inverse mod 2^32
inverse *= 2 - denominator * inverse; // inverse mod 2^64
inverse *= 2 - denominator * inverse; // inverse mod 2^128
inverse *= 2 - denominator * inverse; // inverse mod 2^256
// Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
// This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
// less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
// is no longer required.
result = prod0 * inverse;
return result;
}
}
/**
* @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
*/
function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
uint256 result = mulDiv(x, y, denominator);
if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
result += 1;
}
return result;
}
/**
* @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
*
* Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
*/
function sqrt(uint256 a) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
// For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
//
// We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
// `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
//
// This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
// → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
// → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
//
// Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
uint256 result = 1 << (log2(a) >> 1);
// At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
// since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
// every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
// into the expected uint128 result.
unchecked {
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
return min(result, a / result);
}
}
/**
* @notice Calculates sqrt(a), following the selected rounding direction.
*/
function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = sqrt(a);
return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
}
}
/**
* @dev Return the log in base 2, rounded down, of a positive value.
* Returns 0 if given 0.
*/
function log2(uint256 value) internal pure returns (uint256) {
uint256 result = 0;
unchecked {
if (value >> 128 > 0) {
value >>= 128;
result += 128;
}
if (value >> 64 > 0) {
value >>= 64;
result += 64;
}
if (value >> 32 > 0) {
value >>= 32;
result += 32;
}
if (value >> 16 > 0) {
value >>= 16;
result += 16;
}
if (value >> 8 > 0) {
value >>= 8;
result += 8;
}
if (value >> 4 > 0) {
value >>= 4;
result += 4;
}
if (value >> 2 > 0) {
value >>= 2;
result += 2;
}
if (value >> 1 > 0) {
result += 1;
}
}
return result;
}
/**
* @dev Return the log in base 2, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/
function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = log2(value);
return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
}
}
/**
* @dev Return the log in base 10, rounded down, of a positive value.
* Returns 0 if given 0.
*/
function log10(uint256 value) internal pure returns (uint256) {
uint256 result = 0;
unchecked {
if (value >= 10 ** 64) {
value /= 10 ** 64;
result += 64;
}
if (value >= 10 ** 32) {
value /= 10 ** 32;
result += 32;
}
if (value >= 10 ** 16) {
value /= 10 ** 16;
result += 16;
}
if (value >= 10 ** 8) {
value /= 10 ** 8;
result += 8;
}
if (value >= 10 ** 4) {
value /= 10 ** 4;
result += 4;
}
if (value >= 10 ** 2) {
value /= 10 ** 2;
result += 2;
}
if (value >= 10 ** 1) {
result += 1;
}
}
return result;
}
/**
* @dev Return the log in base 10, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/
function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = log10(value);
return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
}
}
/**
* @dev Return the log in base 256, rounded down, of a positive value.
* Returns 0 if given 0.
*
* Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
*/
function log256(uint256 value) internal pure returns (uint256) {
uint256 result = 0;
unchecked {
if (value >> 128 > 0) {
value >>= 128;
result += 16;
}
if (value >> 64 > 0) {
value >>= 64;
result += 8;
}
if (value >> 32 > 0) {
value >>= 32;
result += 4;
}
if (value >> 16 > 0) {
value >>= 16;
result += 2;
}
if (value >> 8 > 0) {
result += 1;
}
}
return result;
}
/**
* @dev Return the log in base 256, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/
function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = log256(value);
return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/SafeMath.sol)
pragma solidity ^0.8.0;
// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.
/**
* @dev Wrappers over Solidity's arithmetic operations.
*
* NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
* now has built in overflow checking.
*/
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) {
unchecked {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
}
/**
* @dev Returns the subtraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
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) {
unchecked {
// 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) {
unchecked {
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) {
unchecked {
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) {
return a + b;
}
/**
* @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) {
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) {
return a * b;
}
/**
* @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.
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
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) {
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) {
unchecked {
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.
*
* 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) {
unchecked {
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) {
unchecked {
require(b > 0, errorMessage);
return a % b;
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @title anS Token Contract
* @dev ERC20 compatible contract for anS
* @dev Implements an elastic supply
* @author Angles
*/
import { SafeMath } from "@openzeppelin/contracts/utils/math/SafeMath.sol";
import { Address } from "@openzeppelin/contracts/utils/Address.sol";
import { Initializable } from "./utils/Initializable.sol";
import { InitializableERC20Detailed } from "./utils/InitializableERC20Detailed.sol";
import { StableMath } from "./utils/StableMath.sol";
import { Governable } from "./governance/Governable.sol";
/**
* NOTE that this is an ERC20 token but the invariant that the sum of
* balanceOf(x) for all x is not >= totalSupply(). This is a consequence of the
* rebasing design. Any integrations with anS should be aware.
*/
contract anS is Initializable, InitializableERC20Detailed, Governable {
using SafeMath for uint256;
using StableMath for uint256;
event TotalSupplyUpdatedHighres(
uint256 totalSupply,
uint256 rebasingCredits,
uint256 rebasingCreditsPerToken
);
event AccountRebasingEnabled(address account);
event AccountRebasingDisabled(address account);
enum RebaseOptions {
NotSet,
OptOut,
OptIn
}
uint256 private constant MAX_SUPPLY = ~uint128(0); // (2^128) - 1
uint256 public _totalSupply;
mapping(address => mapping(address => uint256)) private _allowances;
address public vaultAddress = address(0);
mapping(address => uint256) private _creditBalances;
uint256 private _rebasingCredits;
uint256 private _rebasingCreditsPerToken;
// Frozen address/credits are non rebasing (value is held in contracts which
// do not receive yield unless they explicitly opt in)
uint256 public nonRebasingSupply;
mapping(address => uint256) public nonRebasingCreditsPerToken;
mapping(address => RebaseOptions) public rebaseState;
mapping(address => uint256) public isUpgraded;
uint256 private constant RESOLUTION_INCREASE = 1e9;
function initialize(
string calldata _nameArg,
string calldata _symbolArg,
address _vaultAddress,
uint256 _initialCreditsPerToken
) external onlyGovernor initializer {
InitializableERC20Detailed._initialize(_nameArg, _symbolArg, 18);
_rebasingCreditsPerToken = _initialCreditsPerToken;
vaultAddress = _vaultAddress;
}
/**
* @dev Verifies that the caller is the Vault contract
*/
modifier onlyVault() {
require(vaultAddress == msg.sender, "Caller is not the Vault");
_;
}
/**
* @dev Only for dev purposes
*/
function changeVault(address _newVault) public onlyGovernor {
vaultAddress = _newVault;
}
/**
* @return The total supply of anS.
*/
function totalSupply() public view override returns (uint256) {
return _totalSupply;
}
/**
* @return Low resolution rebasingCreditsPerToken
*/
function rebasingCreditsPerToken() public view returns (uint256) {
return _rebasingCreditsPerToken / RESOLUTION_INCREASE;
}
/**
* @return Low resolution total number of rebasing credits
*/
function rebasingCredits() public view returns (uint256) {
return _rebasingCredits / RESOLUTION_INCREASE;
}
/**
* @return High resolution rebasingCreditsPerToken
*/
function rebasingCreditsPerTokenHighres() public view returns (uint256) {
return _rebasingCreditsPerToken;
}
/**
* @return High resolution total number of rebasing credits
*/
function rebasingCreditsHighres() public view returns (uint256) {
return _rebasingCredits;
}
/**
* @dev Gets the balance of the specified address.
* @param _account Address to query the balance of.
* @return A uint256 representing the amount of base units owned by the
* specified address.
*/
function balanceOf(address _account)
public
view
override
returns (uint256)
{
if (_creditBalances[_account] == 0) return 0;
return
_creditBalances[_account].divPrecisely(_creditsPerToken(_account));
}
/**
* @dev Gets the credits balance of the specified address.
* @dev Backwards compatible with old low res credits per token.
* @param _account The address to query the balance of.
* @return (uint256, uint256) Credit balance and credits per token of the
* address
*/
function creditsBalanceOf(address _account)
public
view
returns (uint256, uint256)
{
uint256 cpt = _creditsPerToken(_account);
if (cpt == 1e27) {
// For a period before the resolution upgrade, we created all new
// contract accounts at high resolution. Since they are not changing
// as a result of this upgrade, we will return their true values
return (_creditBalances[_account], cpt);
} else {
return (
_creditBalances[_account] / RESOLUTION_INCREASE,
cpt / RESOLUTION_INCREASE
);
}
}
/**
* @dev Gets the credits balance of the specified address.
* @param _account The address to query the balance of.
* @return (uint256, uint256, bool) Credit balance, credits per token of the
* address, and isUpgraded
*/
function creditsBalanceOfHighres(address _account)
public
view
returns (
uint256,
uint256,
bool
)
{
return (
_creditBalances[_account],
_creditsPerToken(_account),
isUpgraded[_account] == 1
);
}
/**
* @dev Transfer tokens to a specified address.
* @param _to the address to transfer to.
* @param _value the amount to be transferred.
* @return true on success.
*/
function transfer(address _to, uint256 _value)
public
override
returns (bool)
{
require(_to != address(0), "Transfer to zero address");
require(
_value <= balanceOf(msg.sender),
"Transfer greater than balance"
);
_executeTransfer(msg.sender, _to, _value);
emit Transfer(msg.sender, _to, _value);
return true;
}
/**
* @dev Transfer tokens from one address to another.
* @param _from The address you want to send tokens from.
* @param _to The address you want to transfer to.
* @param _value The amount of tokens to be transferred.
*/
function transferFrom(
address _from,
address _to,
uint256 _value
) public override returns (bool) {
require(_to != address(0), "Transfer to zero address");
require(_value <= balanceOf(_from), "Transfer greater than balance");
_allowances[_from][msg.sender] = _allowances[_from][msg.sender].sub(
_value
);
_executeTransfer(_from, _to, _value);
emit Transfer(_from, _to, _value);
return true;
}
/**
* @dev Update the count of non rebasing credits in response to a transfer
* @param _from The address you want to send tokens from.
* @param _to The address you want to transfer to.
* @param _value Amount of anS to transfer
*/
function _executeTransfer(
address _from,
address _to,
uint256 _value
) internal {
bool isNonRebasingTo = _isNonRebasingAccount(_to);
bool isNonRebasingFrom = _isNonRebasingAccount(_from);
// Credits deducted and credited might be different due to the
// differing creditsPerToken used by each account
uint256 creditsCredited = _value.mulTruncate(_creditsPerToken(_to));
uint256 creditsDeducted = _value.mulTruncate(_creditsPerToken(_from));
_creditBalances[_from] = _creditBalances[_from].sub(
creditsDeducted,
"Transfer amount exceeds balance"
);
_creditBalances[_to] = _creditBalances[_to].add(creditsCredited);
if (isNonRebasingTo && !isNonRebasingFrom) {
// Transfer to non-rebasing account from rebasing account, credits
// are removed from the non rebasing tally
nonRebasingSupply = nonRebasingSupply.add(_value);
// Update rebasingCredits by subtracting the deducted amount
_rebasingCredits = _rebasingCredits.sub(creditsDeducted);
} else if (!isNonRebasingTo && isNonRebasingFrom) {
// Transfer to rebasing account from non-rebasing account
// Decreasing non-rebasing credits by the amount that was sent
nonRebasingSupply = nonRebasingSupply.sub(_value);
// Update rebasingCredits by adding the credited amount
_rebasingCredits = _rebasingCredits.add(creditsCredited);
}
}
/**
* @dev Function to check the amount of tokens that _owner has allowed to
* `_spender`.
* @param _owner The address which owns the funds.
* @param _spender The address which will spend the funds.
* @return The number of tokens still available for the _spender.
*/
function allowance(address _owner, address _spender)
public
view
override
returns (uint256)
{
return _allowances[_owner][_spender];
}
/**
* @dev Approve the passed address to spend the specified amount of tokens
* on behalf of msg.sender. This method is included for ERC20
* compatibility. `increaseAllowance` and `decreaseAllowance` should be
* used instead.
*
* Changing an allowance with this method brings the risk that someone
* may transfer both the old and the new allowance - if they are both
* greater than zero - if a transfer transaction is mined before the
* later approve() call is mined.
* @param _spender The address which will spend the funds.
* @param _value The amount of tokens to be spent.
*/
function approve(address _spender, uint256 _value)
public
override
returns (bool)
{
_allowances[msg.sender][_spender] = _value;
emit Approval(msg.sender, _spender, _value);
return true;
}
/**
* @dev Increase the amount of tokens that an owner has allowed to
* `_spender`.
* This method should be used instead of approve() to avoid the double
* approval vulnerability described above.
* @param _spender The address which will spend the funds.
* @param _addedValue The amount of tokens to increase the allowance by.
*/
function increaseAllowance(address _spender, uint256 _addedValue)
public
returns (bool)
{
_allowances[msg.sender][_spender] = _allowances[msg.sender][_spender]
.add(_addedValue);
emit Approval(msg.sender, _spender, _allowances[msg.sender][_spender]);
return true;
}
/**
* @dev Decrease the amount of tokens that an owner has allowed to
`_spender`.
* @param _spender The address which will spend the funds.
* @param _subtractedValue The amount of tokens to decrease the allowance
* by.
*/
function decreaseAllowance(address _spender, uint256 _subtractedValue)
public
returns (bool)
{
uint256 oldValue = _allowances[msg.sender][_spender];
if (_subtractedValue >= oldValue) {
_allowances[msg.sender][_spender] = 0;
} else {
_allowances[msg.sender][_spender] = oldValue.sub(_subtractedValue);
}
emit Approval(msg.sender, _spender, _allowances[msg.sender][_spender]);
return true;
}
/**
* @dev Mints new tokens, increasing totalSupply.
*/
function mint(address _account, uint256 _amount) external onlyVault {
_mint(_account, _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 nonReentrant {
require(_account != address(0), "Mint to the zero address");
bool isNonRebasingAccount = _isNonRebasingAccount(_account);
uint256 creditAmount = _amount.mulTruncate(_creditsPerToken(_account));
_creditBalances[_account] = _creditBalances[_account].add(creditAmount);
// If the account is non rebasing and doesn't have a set creditsPerToken
// then set it i.e. this is a mint from a fresh contract
if (isNonRebasingAccount) {
nonRebasingSupply = nonRebasingSupply.add(_amount);
} else {
_rebasingCredits = _rebasingCredits.add(creditAmount);
}
_totalSupply = _totalSupply.add(_amount);
require(_totalSupply < MAX_SUPPLY, "Max supply");
emit Transfer(address(0), _account, _amount);
}
/**
* @dev Burns tokens, decreasing totalSupply.
*/
function burn(address account, uint256 amount) external onlyVault {
_burn(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 nonReentrant {
require(_account != address(0), "Burn from the zero address");
if (_amount == 0) {
return;
}
bool isNonRebasingAccount = _isNonRebasingAccount(_account);
uint256 creditAmount = _amount.mulTruncate(_creditsPerToken(_account));
uint256 currentCredits = _creditBalances[_account];
// Remove the credits, burning rounding errors
if (
currentCredits == creditAmount || currentCredits - 1 == creditAmount
) {
// Handle dust from rounding
_creditBalances[_account] = 0;
} else if (currentCredits > creditAmount) {
_creditBalances[_account] = _creditBalances[_account].sub(
creditAmount
);
} else {
revert("Remove exceeds balance");
}
// Remove from the credit tallies and non-rebasing supply
if (isNonRebasingAccount) {
nonRebasingSupply = nonRebasingSupply.sub(_amount);
} else {
_rebasingCredits = _rebasingCredits.sub(creditAmount);
}
_totalSupply = _totalSupply.sub(_amount);
emit Transfer(_account, address(0), _amount);
}
/**
* @dev Get the credits per token for an account. Returns a fixed amount
* if the account is non-rebasing.
* @param _account Address of the account.
*/
function _creditsPerToken(address _account)
internal
view
returns (uint256)
{
if (nonRebasingCreditsPerToken[_account] != 0) {
return nonRebasingCreditsPerToken[_account];
} else {
return _rebasingCreditsPerToken;
}
}
/**
* @dev Is an account using rebasing accounting or non-rebasing accounting?
* Also, ensure contracts are non-rebasing if they have not opted in.
* @param _account Address of the account.
*/
function _isNonRebasingAccount(address _account) internal returns (bool) {
bool isContract = Address.isContract(_account);
if (isContract && rebaseState[_account] == RebaseOptions.NotSet) {
_ensureRebasingMigration(_account);
}
return nonRebasingCreditsPerToken[_account] > 0;
}
/**
* @dev Ensures internal account for rebasing and non-rebasing credits and
* supply is updated following deployment of frozen yield change.
*/
function _ensureRebasingMigration(address _account) internal {
if (nonRebasingCreditsPerToken[_account] == 0) {
emit AccountRebasingDisabled(_account);
if (_creditBalances[_account] == 0) {
// Since there is no existing balance, we can directly set to
// high resolution, and do not have to do any other bookkeeping
nonRebasingCreditsPerToken[_account] = 1e27;
} else {
// Migrate an existing account:
// Set fixed credits per token for this account
nonRebasingCreditsPerToken[_account] = _rebasingCreditsPerToken;
// Update non rebasing supply
nonRebasingSupply = nonRebasingSupply.add(balanceOf(_account));
// Update credit tallies
_rebasingCredits = _rebasingCredits.sub(
_creditBalances[_account]
);
}
}
}
/**
* @notice Enable rebasing for an account.
* @dev Add a contract address to the non-rebasing exception list. The
* address's balance will be part of rebases and the account will be exposed
* to upside and downside.
* @param _account Address of the account.
*/
function governanceRebaseOptIn(address _account)
public
nonReentrant
onlyGovernor
{
_rebaseOptIn(_account);
}
/**
* @dev Add a contract address to the non-rebasing exception list. The
* address's balance will be part of rebases and the account will be exposed
* to upside and downside.
*/
function rebaseOptIn() public nonReentrant {
_rebaseOptIn(msg.sender);
}
function _rebaseOptIn(address _account) internal {
require(_isNonRebasingAccount(_account), "Account has not opted out");
// Convert balance into the same amount at the current exchange rate
uint256 newCreditBalance = _creditBalances[_account]
.mul(_rebasingCreditsPerToken)
.div(_creditsPerToken(_account));
// Decreasing non rebasing supply
nonRebasingSupply = nonRebasingSupply.sub(balanceOf(_account));
_creditBalances[_account] = newCreditBalance;
// Increase rebasing credits, totalSupply remains unchanged so no
// adjustment necessary
_rebasingCredits = _rebasingCredits.add(_creditBalances[_account]);
rebaseState[_account] = RebaseOptions.OptIn;
// Delete any fixed credits per token
delete nonRebasingCreditsPerToken[_account];
emit AccountRebasingEnabled(_account);
}
/**
* @dev Explicitly mark that an address is non-rebasing.
*/
function rebaseOptOut() public nonReentrant {
require(!_isNonRebasingAccount(msg.sender), "Account has not opted in");
// Increase non rebasing supply
nonRebasingSupply = nonRebasingSupply.add(balanceOf(msg.sender));
// Set fixed credits per token
nonRebasingCreditsPerToken[msg.sender] = _rebasingCreditsPerToken;
// Decrease rebasing credits, total supply remains unchanged so no
// adjustment necessary
_rebasingCredits = _rebasingCredits.sub(_creditBalances[msg.sender]);
// Mark explicitly opted out of rebasing
rebaseState[msg.sender] = RebaseOptions.OptOut;
emit AccountRebasingDisabled(msg.sender);
}
/**
* @dev Modify the supply without minting new tokens. This uses a change in
* the exchange rate between "credits" and anS tokens to change balances.
* @param _newTotalSupply New total supply of anS.
*/
function changeSupply(uint256 _newTotalSupply)
external
onlyVault
nonReentrant
{
require(_totalSupply > 0, "Cannot increase 0 supply");
if (_totalSupply == _newTotalSupply) {
emit TotalSupplyUpdatedHighres(
_totalSupply,
_rebasingCredits,
_rebasingCreditsPerToken
);
return;
}
_totalSupply = _newTotalSupply > MAX_SUPPLY
? MAX_SUPPLY
: _newTotalSupply;
_rebasingCreditsPerToken = _rebasingCredits.divPrecisely(
_totalSupply.sub(nonRebasingSupply)
);
require(_rebasingCreditsPerToken > 0, "Invalid change in supply");
_totalSupply = _rebasingCredits
.divPrecisely(_rebasingCreditsPerToken)
.add(nonRebasingSupply);
emit TotalSupplyUpdatedHighres(
_totalSupply,
_rebasingCredits,
_rebasingCreditsPerToken
);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @title Base for contracts that are managed by the Origin Protocol's Governor.
* @dev Copy of the openzeppelin Ownable.sol contract with nomenclature change
* from owner to governor and renounce methods removed. Does not use
* Context.sol like Ownable.sol does for simplification.
* @author Origin Protocol Inc
*/
contract Governable {
// Storage position of the owner and pendingOwner of the contract
// keccak256("OUSD.governor");
bytes32 private constant governorPosition =
0x7bea13895fa79d2831e0a9e28edede30099005a50d652d8957cf8a607ee6ca4a;
// keccak256("OUSD.pending.governor");
bytes32 private constant pendingGovernorPosition =
0x44c4d30b2eaad5130ad70c3ba6972730566f3e6359ab83e800d905c61b1c51db;
// keccak256("OUSD.reentry.status");
bytes32 private constant reentryStatusPosition =
0x53bf423e48ed90e97d02ab0ebab13b2a235a6bfbe9c321847d5c175333ac4535;
// See OpenZeppelin ReentrancyGuard implementation
uint256 constant _NOT_ENTERED = 1;
uint256 constant _ENTERED = 2;
event PendingGovernorshipTransfer(
address indexed previousGovernor,
address indexed newGovernor
);
event GovernorshipTransferred(
address indexed previousGovernor,
address indexed newGovernor
);
/**
* @dev Initializes the contract setting the deployer as the initial Governor.
*/
constructor() {
_setGovernor(msg.sender);
emit GovernorshipTransferred(address(0), _governor());
}
/**
* @notice Returns the address of the current Governor.
*/
function governor() public view returns (address) {
return _governor();
}
/**
* @dev Returns the address of the current Governor.
*/
function _governor() internal view returns (address governorOut) {
bytes32 position = governorPosition;
// solhint-disable-next-line no-inline-assembly
assembly {
governorOut := sload(position)
}
}
/**
* @dev Returns the address of the pending Governor.
*/
function _pendingGovernor()
internal
view
returns (address pendingGovernor)
{
bytes32 position = pendingGovernorPosition;
// solhint-disable-next-line no-inline-assembly
assembly {
pendingGovernor := sload(position)
}
}
/**
* @dev Throws if called by any account other than the Governor.
*/
modifier onlyGovernor() {
require(isGovernor(), "Caller is not the Governor");
_;
}
/**
* @notice Returns true if the caller is the current Governor.
*/
function isGovernor() public view returns (bool) {
return msg.sender == _governor();
}
function _setGovernor(address newGovernor) internal {
bytes32 position = governorPosition;
// solhint-disable-next-line no-inline-assembly
assembly {
sstore(position, newGovernor)
}
}
/**
* @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() {
bytes32 position = reentryStatusPosition;
uint256 _reentry_status;
// solhint-disable-next-line no-inline-assembly
assembly {
_reentry_status := sload(position)
}
// On the first call to nonReentrant, _notEntered will be true
require(_reentry_status != _ENTERED, "Reentrant call");
// Any calls to nonReentrant after this point will fail
// solhint-disable-next-line no-inline-assembly
assembly {
sstore(position, _ENTERED)
}
_;
// By storing the original value once again, a refund is triggered (see
// https://eips.ethereum.org/EIPS/eip-2200)
// solhint-disable-next-line no-inline-assembly
assembly {
sstore(position, _NOT_ENTERED)
}
}
function _setPendingGovernor(address newGovernor) internal {
bytes32 position = pendingGovernorPosition;
// solhint-disable-next-line no-inline-assembly
assembly {
sstore(position, newGovernor)
}
}
/**
* @notice Transfers Governance of the contract to a new account (`newGovernor`).
* Can only be called by the current Governor. Must be claimed for this to complete
* @param _newGovernor Address of the new Governor
*/
function transferGovernance(address _newGovernor) external onlyGovernor {
_setPendingGovernor(_newGovernor);
emit PendingGovernorshipTransfer(_governor(), _newGovernor);
}
/**
* @notice Claim Governance of the contract to a new account (`newGovernor`).
* Can only be called by the new Governor.
*/
function claimGovernance() external {
require(
msg.sender == _pendingGovernor(),
"Only the pending Governor can complete the claim"
);
_changeGovernor(msg.sender);
}
/**
* @dev Change Governance of the contract to a new account (`newGovernor`).
* @param _newGovernor Address of the new Governor
*/
function _changeGovernor(address _newGovernor) internal {
require(_newGovernor != address(0), "New Governor is address(0)");
emit GovernorshipTransferred(_governor(), _newGovernor);
_setGovernor(_newGovernor);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @title Base contract any contracts that need to initialize state after deployment.
* @author Origin Protocol Inc
*/
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 || !initialized,
"Initializable: contract is already initialized"
);
bool isTopLevelCall = !initializing;
if (isTopLevelCall) {
initializing = true;
initialized = true;
}
_;
if (isTopLevelCall) {
initializing = false;
}
}
uint256[50] private ______gap;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
/**
* @dev Optional functions from the ERC20 standard.
* Converted from openzeppelin/contracts/token/ERC20/ERC20Detailed.sol
* @author Origin Protocol Inc
*/
abstract contract InitializableERC20Detailed is IERC20 {
// Storage gap to skip storage from prior to OUSD reset
uint256[100] private _____gap;
string private _name;
string private _symbol;
uint8 private _decimals;
/**
* @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
* these values are immutable: they can only be set once during
* construction.
* @notice To avoid variable shadowing appended `Arg` after arguments name.
*/
function _initialize(
string memory nameArg,
string memory symbolArg,
uint8 decimalsArg
) internal {
_name = nameArg;
_symbol = symbolArg;
_decimals = decimalsArg;
}
/**
* @notice Returns the name of the token.
*/
function name() public view returns (string memory) {
return _name;
}
/**
* @notice Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view returns (string memory) {
return _symbol;
}
/**
* @notice 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.
*
* 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 returns (uint8) {
return _decimals;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import { SafeMath } from "@openzeppelin/contracts/utils/math/SafeMath.sol";
// Based on StableMath from Stability Labs Pty. Ltd.
// https://github.com/mstable/mStable-contracts/blob/master/contracts/shared/StableMath.sol
library StableMath {
using SafeMath for uint256;
/**
* @dev Scaling unit for use in specific calculations,
* where 1 * 10**18, or 1e18 represents a unit '1'
*/
uint256 private constant FULL_SCALE = 1e18;
/***************************************
Helpers
****************************************/
/**
* @dev Adjust the scale of an integer
* @param to Decimals to scale to
* @param from Decimals to scale from
*/
function scaleBy(
uint256 x,
uint256 to,
uint256 from
) internal pure returns (uint256) {
if (to > from) {
x = x.mul(10**(to - from));
} else if (to < from) {
// slither-disable-next-line divide-before-multiply
x = x.div(10**(from - to));
}
return x;
}
/***************************************
Precise Arithmetic
****************************************/
/**
* @dev Multiplies two precise units, and then truncates by the full scale
* @param x Left hand input to multiplication
* @param y Right hand input to multiplication
* @return Result after multiplying the two inputs and then dividing by the shared
* scale unit
*/
function mulTruncate(uint256 x, uint256 y) internal pure returns (uint256) {
return mulTruncateScale(x, y, FULL_SCALE);
}
/**
* @dev Multiplies two precise units, and then truncates by the given scale. For example,
* when calculating 90% of 10e18, (10e18 * 9e17) / 1e18 = (9e36) / 1e18 = 9e18
* @param x Left hand input to multiplication
* @param y Right hand input to multiplication
* @param scale Scale unit
* @return Result after multiplying the two inputs and then dividing by the shared
* scale unit
*/
function mulTruncateScale(
uint256 x,
uint256 y,
uint256 scale
) internal pure returns (uint256) {
// e.g. assume scale = fullScale
// z = 10e18 * 9e17 = 9e36
uint256 z = x.mul(y);
// return 9e36 / 1e18 = 9e18
return z.div(scale);
}
/**
* @dev Multiplies two precise units, and then truncates by the full scale, rounding up the result
* @param x Left hand input to multiplication
* @param y Right hand input to multiplication
* @return Result after multiplying the two inputs and then dividing by the shared
* scale unit, rounded up to the closest base unit.
*/
function mulTruncateCeil(uint256 x, uint256 y)
internal
pure
returns (uint256)
{
// e.g. 8e17 * 17268172638 = 138145381104e17
uint256 scaled = x.mul(y);
// e.g. 138145381104e17 + 9.99...e17 = 138145381113.99...e17
uint256 ceil = scaled.add(FULL_SCALE.sub(1));
// e.g. 13814538111.399...e18 / 1e18 = 13814538111
return ceil.div(FULL_SCALE);
}
/**
* @dev Precisely divides two units, by first scaling the left hand operand. Useful
* for finding percentage weightings, i.e. 8e18/10e18 = 80% (or 8e17)
* @param x Left hand input to division
* @param y Right hand input to division
* @return Result after multiplying the left operand by the scale, and
* executing the division on the right hand input.
*/
function divPrecisely(uint256 x, uint256 y)
internal
pure
returns (uint256)
{
// e.g. 8e18 * 1e18 = 8e36
uint256 z = x.mul(FULL_SCALE);
// e.g. 8e36 / 10e18 = 8e17
return z.div(y);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import { IERC20Metadata } from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import { ERC4626 } from "@openzeppelin/contracts/token/ERC20/extensions/ERC4626.sol";
import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import { Governable } from "./governance/Governable.sol";
import { Initializable } from "./utils/Initializable.sol";
import { anS } from "./anS.sol";
/**
* @title Wrapped anS Token Contract
* @author Angles
*/
contract wanS is ERC4626, Governable, Initializable {
using SafeERC20 for IERC20;
constructor(
ERC20 underlying_,
string memory name_,
string memory symbol_
) ERC20(name_, symbol_) ERC4626(underlying_) Governable() {}
/**
* @notice Enable anS rebasing for this contract
*/
function initialize() external onlyGovernor initializer {
anS(address(asset())).rebaseOptIn();
}
function name() public view virtual override(ERC20,IERC20Metadata) returns (string memory) {
return "Wrapped anS";
}
function symbol() public view virtual override(ERC20,IERC20Metadata) returns (string memory) {
return "wanS";
}
/**
* @notice Transfer token to governor. Intended for recovering tokens stuck in
* contract, i.e. mistaken sends. Cannot transfer anS
* @param asset_ Address for the asset
* @param amount_ Amount of the asset to transfer
*/
function transferToken(address asset_, uint256 amount_)
external
onlyGovernor
{
require(asset_ != address(asset()), "Cannot collect anS");
IERC20(asset_).safeTransfer(governor(), amount_);
}
}