Contract Source Code:
// SPDX-License-Identifier: MIT
// solhint-disable-next-line compiler-version
pragma solidity >=0.4.24 <0.8.0;
import "../utils/AddressUpgradeable.sol";
/**
* @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
* behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
* external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
* function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
*
* TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
* possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
*
* CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
* that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
*/
abstract contract Initializable {
/**
* @dev Indicates that the contract has been initialized.
*/
bool private _initialized;
/**
* @dev Indicates that the contract is in the process of being initialized.
*/
bool private _initializing;
/**
* @dev Modifier to protect an initializer function from being invoked twice.
*/
modifier initializer() {
require(_initializing || _isConstructor() || !_initialized, "Initializable: contract is already initialized");
bool isTopLevelCall = !_initializing;
if (isTopLevelCall) {
_initializing = true;
_initialized = true;
}
_;
if (isTopLevelCall) {
_initializing = false;
}
}
/// @dev Returns true if and only if the function is running in the constructor
function _isConstructor() private view returns (bool) {
return !AddressUpgradeable.isContract(address(this));
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.2 <0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library AddressUpgradeable {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
// solhint-disable-next-line no-inline-assembly
assembly { size := extcodesize(account) }
return size > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "./IERC165.sol";
/**
* @dev Implementation of the {IERC165} interface.
*
* Contracts may inherit from this and call {_registerInterface} to declare
* their support of an interface.
*/
abstract contract ERC165 is IERC165 {
/*
* bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
*/
bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
/**
* @dev Mapping of interface ids to whether or not it's supported.
*/
mapping(bytes4 => bool) private _supportedInterfaces;
constructor () internal {
// Derived contracts need only register support for their own interfaces,
// we register support for ERC165 itself here
_registerInterface(_INTERFACE_ID_ERC165);
}
/**
* @dev See {IERC165-supportsInterface}.
*
* Time complexity O(1), guaranteed to always use less than 30 000 gas.
*/
function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
return _supportedInterfaces[interfaceId];
}
/**
* @dev Registers the contract as an implementer of the interface defined by
* `interfaceId`. Support of the actual ERC165 interface is automatic and
* registering its interface id is not required.
*
* See {IERC165-supportsInterface}.
*
* Requirements:
*
* - `interfaceId` cannot be the ERC165 invalid interface (`0xffffffff`).
*/
function _registerInterface(bytes4 interfaceId) internal virtual {
require(interfaceId != 0xffffffff, "ERC165: invalid interface id");
_supportedInterfaces[interfaceId] = true;
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Interface of the ERC165 standard, as defined in the
* https://eips.ethereum.org/EIPS/eip-165[EIP].
*
* Implementers can declare support of contract interfaces, which can then be
* queried by others ({ERC165Checker}).
*
* For an implementation, see {ERC165}.
*/
interface IERC165 {
/**
* @dev Returns true if this contract implements the interface defined by
* `interfaceId`. See the corresponding
* https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
* to learn more about how these ids are created.
*
* This function call must use less than 30 000 gas.
*/
function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
/**
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b > a) return (false, 0);
return (true, a - b);
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) return (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b == 0) return (false, 0);
return (true, a / b);
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
if (b == 0) return (false, 0);
return (true, a % b);
}
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
require(b <= a, "SafeMath: subtraction overflow");
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) return 0;
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
require(b > 0, "SafeMath: division by zero");
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
require(b > 0, "SafeMath: modulo by zero");
return a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
return a - b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
* division by zero. The result is rounded towards zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryDiv}.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
return a % b;
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev https://eips.ethereum.org/EIPS/eip-1167[EIP 1167] is a standard for
* deploying minimal proxy contracts, also known as "clones".
*
* > To simply and cheaply clone contract functionality in an immutable way, this standard specifies
* > a minimal bytecode implementation that delegates all calls to a known, fixed address.
*
* The library includes functions to deploy a proxy using either `create` (traditional deployment) or `create2`
* (salted deterministic deployment). It also includes functions to predict the addresses of clones deployed using the
* deterministic method.
*
* _Available since v3.4._
*/
library Clones {
/**
* @dev Deploys and returns the address of a clone that mimics the behaviour of `master`.
*
* This function uses the create opcode, which should never revert.
*/
function clone(address master) internal returns (address instance) {
// solhint-disable-next-line no-inline-assembly
assembly {
let ptr := mload(0x40)
mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
mstore(add(ptr, 0x14), shl(0x60, master))
mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000)
instance := create(0, ptr, 0x37)
}
require(instance != address(0), "ERC1167: create failed");
}
/**
* @dev Deploys and returns the address of a clone that mimics the behaviour of `master`.
*
* This function uses the create2 opcode and a `salt` to deterministically deploy
* the clone. Using the same `master` and `salt` multiple time will revert, since
* the clones cannot be deployed twice at the same address.
*/
function cloneDeterministic(address master, bytes32 salt) internal returns (address instance) {
// solhint-disable-next-line no-inline-assembly
assembly {
let ptr := mload(0x40)
mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
mstore(add(ptr, 0x14), shl(0x60, master))
mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000)
instance := create2(0, ptr, 0x37, salt)
}
require(instance != address(0), "ERC1167: create2 failed");
}
/**
* @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
*/
function predictDeterministicAddress(address master, bytes32 salt, address deployer) internal pure returns (address predicted) {
// solhint-disable-next-line no-inline-assembly
assembly {
let ptr := mload(0x40)
mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
mstore(add(ptr, 0x14), shl(0x60, master))
mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf3ff00000000000000000000000000000000)
mstore(add(ptr, 0x38), shl(0x60, deployer))
mstore(add(ptr, 0x4c), salt)
mstore(add(ptr, 0x6c), keccak256(ptr, 0x37))
predicted := keccak256(add(ptr, 0x37), 0x55)
}
}
/**
* @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
*/
function predictDeterministicAddress(address master, bytes32 salt) internal view returns (address predicted) {
return predictDeterministicAddress(master, salt, address(this));
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../../utils/Context.sol";
import "./IERC20.sol";
import "../../math/SafeMath.sol";
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin guidelines: functions revert instead
* of returning `false` on failure. This behavior is nonetheless conventional
* and does not conflict with the expectations of ERC20 applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20 {
using SafeMath for uint256;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
/**
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with
* a default value of 18.
*
* To select a different value for {decimals}, use {_setupDecimals}.
*
* All three of these values are immutable: they can only be set once during
* construction.
*/
constructor (string memory name_, string memory symbol_) public {
_name = name_;
_symbol = symbol_;
_decimals = 18;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5,05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
* called.
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view virtual returns (uint8) {
return _decimals;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* Requirements:
*
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for ``sender``'s tokens of at least
* `amount`.
*/
function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
return true;
}
/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(address sender, address recipient, uint256 amount) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `to` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(address owner, address spender, uint256 amount) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Sets {decimals} to a value other than the default one of 18.
*
* WARNING: This function should only be called from the constructor. Most
* applications that interact with token contracts will not expect
* {decimals} to ever change, and may work incorrectly if it does.
*/
function _setupDecimals(uint8 decimals_) internal virtual {
_decimals = decimals_;
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be to transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "./IERC20.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using SafeMath for uint256;
using Address for address;
function safeTransfer(IERC20 token, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(IERC20 token, address spender, uint256 value) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
// solhint-disable-next-line max-line-length
require((value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).add(value);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) { // Return data is optional
// solhint-disable-next-line max-line-length
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../../utils/Context.sol";
import "./IERC721.sol";
import "./IERC721Metadata.sol";
import "./IERC721Enumerable.sol";
import "./IERC721Receiver.sol";
import "../../introspection/ERC165.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";
import "../../utils/EnumerableSet.sol";
import "../../utils/EnumerableMap.sol";
import "../../utils/Strings.sol";
/**
* @title ERC721 Non-Fungible Token Standard basic implementation
* @dev see https://eips.ethereum.org/EIPS/eip-721
*/
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata, IERC721Enumerable {
using SafeMath for uint256;
using Address for address;
using EnumerableSet for EnumerableSet.UintSet;
using EnumerableMap for EnumerableMap.UintToAddressMap;
using Strings for uint256;
// Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
// which can be also obtained as `IERC721Receiver(0).onERC721Received.selector`
bytes4 private constant _ERC721_RECEIVED = 0x150b7a02;
// Mapping from holder address to their (enumerable) set of owned tokens
mapping (address => EnumerableSet.UintSet) private _holderTokens;
// Enumerable mapping from token ids to their owners
EnumerableMap.UintToAddressMap private _tokenOwners;
// Mapping from token ID to approved address
mapping (uint256 => address) private _tokenApprovals;
// Mapping from owner to operator approvals
mapping (address => mapping (address => bool)) private _operatorApprovals;
// Token name
string private _name;
// Token symbol
string private _symbol;
// Optional mapping for token URIs
mapping (uint256 => string) private _tokenURIs;
// Base URI
string private _baseURI;
/*
* bytes4(keccak256('balanceOf(address)')) == 0x70a08231
* bytes4(keccak256('ownerOf(uint256)')) == 0x6352211e
* bytes4(keccak256('approve(address,uint256)')) == 0x095ea7b3
* bytes4(keccak256('getApproved(uint256)')) == 0x081812fc
* bytes4(keccak256('setApprovalForAll(address,bool)')) == 0xa22cb465
* bytes4(keccak256('isApprovedForAll(address,address)')) == 0xe985e9c5
* bytes4(keccak256('transferFrom(address,address,uint256)')) == 0x23b872dd
* bytes4(keccak256('safeTransferFrom(address,address,uint256)')) == 0x42842e0e
* bytes4(keccak256('safeTransferFrom(address,address,uint256,bytes)')) == 0xb88d4fde
*
* => 0x70a08231 ^ 0x6352211e ^ 0x095ea7b3 ^ 0x081812fc ^
* 0xa22cb465 ^ 0xe985e9c5 ^ 0x23b872dd ^ 0x42842e0e ^ 0xb88d4fde == 0x80ac58cd
*/
bytes4 private constant _INTERFACE_ID_ERC721 = 0x80ac58cd;
/*
* bytes4(keccak256('name()')) == 0x06fdde03
* bytes4(keccak256('symbol()')) == 0x95d89b41
* bytes4(keccak256('tokenURI(uint256)')) == 0xc87b56dd
*
* => 0x06fdde03 ^ 0x95d89b41 ^ 0xc87b56dd == 0x5b5e139f
*/
bytes4 private constant _INTERFACE_ID_ERC721_METADATA = 0x5b5e139f;
/*
* bytes4(keccak256('totalSupply()')) == 0x18160ddd
* bytes4(keccak256('tokenOfOwnerByIndex(address,uint256)')) == 0x2f745c59
* bytes4(keccak256('tokenByIndex(uint256)')) == 0x4f6ccce7
*
* => 0x18160ddd ^ 0x2f745c59 ^ 0x4f6ccce7 == 0x780e9d63
*/
bytes4 private constant _INTERFACE_ID_ERC721_ENUMERABLE = 0x780e9d63;
/**
* @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
*/
constructor (string memory name_, string memory symbol_) public {
_name = name_;
_symbol = symbol_;
// register the supported interfaces to conform to ERC721 via ERC165
_registerInterface(_INTERFACE_ID_ERC721);
_registerInterface(_INTERFACE_ID_ERC721_METADATA);
_registerInterface(_INTERFACE_ID_ERC721_ENUMERABLE);
}
/**
* @dev See {IERC721-balanceOf}.
*/
function balanceOf(address owner) public view virtual override returns (uint256) {
require(owner != address(0), "ERC721: balance query for the zero address");
return _holderTokens[owner].length();
}
/**
* @dev See {IERC721-ownerOf}.
*/
function ownerOf(uint256 tokenId) public view virtual override returns (address) {
return _tokenOwners.get(tokenId, "ERC721: owner query for nonexistent token");
}
/**
* @dev See {IERC721Metadata-name}.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev See {IERC721Metadata-symbol}.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev See {IERC721Metadata-tokenURI}.
*/
function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
string memory _tokenURI = _tokenURIs[tokenId];
string memory base = baseURI();
// If there is no base URI, return the token URI.
if (bytes(base).length == 0) {
return _tokenURI;
}
// If both are set, concatenate the baseURI and tokenURI (via abi.encodePacked).
if (bytes(_tokenURI).length > 0) {
return string(abi.encodePacked(base, _tokenURI));
}
// If there is a baseURI but no tokenURI, concatenate the tokenID to the baseURI.
return string(abi.encodePacked(base, tokenId.toString()));
}
/**
* @dev Returns the base URI set via {_setBaseURI}. This will be
* automatically added as a prefix in {tokenURI} to each token's URI, or
* to the token ID if no specific URI is set for that token ID.
*/
function baseURI() public view virtual returns (string memory) {
return _baseURI;
}
/**
* @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.
*/
function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {
return _holderTokens[owner].at(index);
}
/**
* @dev See {IERC721Enumerable-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
// _tokenOwners are indexed by tokenIds, so .length() returns the number of tokenIds
return _tokenOwners.length();
}
/**
* @dev See {IERC721Enumerable-tokenByIndex}.
*/
function tokenByIndex(uint256 index) public view virtual override returns (uint256) {
(uint256 tokenId, ) = _tokenOwners.at(index);
return tokenId;
}
/**
* @dev See {IERC721-approve}.
*/
function approve(address to, uint256 tokenId) public virtual override {
address owner = ERC721.ownerOf(tokenId);
require(to != owner, "ERC721: approval to current owner");
require(_msgSender() == owner || ERC721.isApprovedForAll(owner, _msgSender()),
"ERC721: approve caller is not owner nor approved for all"
);
_approve(to, tokenId);
}
/**
* @dev See {IERC721-getApproved}.
*/
function getApproved(uint256 tokenId) public view virtual override returns (address) {
require(_exists(tokenId), "ERC721: approved query for nonexistent token");
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/
function setApprovalForAll(address operator, bool approved) public virtual override {
require(operator != _msgSender(), "ERC721: approve to caller");
_operatorApprovals[_msgSender()][operator] = approved;
emit ApprovalForAll(_msgSender(), operator, approved);
}
/**
* @dev See {IERC721-isApprovedForAll}.
*/
function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
return _operatorApprovals[owner][operator];
}
/**
* @dev See {IERC721-transferFrom}.
*/
function transferFrom(address from, address to, uint256 tokenId) public virtual override {
//solhint-disable-next-line max-line-length
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_transfer(from, to, tokenId);
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/
function safeTransferFrom(address from, address to, uint256 tokenId) public virtual override {
safeTransferFrom(from, to, tokenId, "");
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/
function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public virtual override {
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_safeTransfer(from, to, tokenId, _data);
}
/**
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
* are aware of the ERC721 protocol to prevent tokens from being forever locked.
*
* `_data` is additional data, it has no specified format and it is sent in call to `to`.
*
* This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
* implement alternative mechanisms to perform token transfer, such as signature-based.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function _safeTransfer(address from, address to, uint256 tokenId, bytes memory _data) internal virtual {
_transfer(from, to, tokenId);
require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
}
/**
* @dev Returns whether `tokenId` exists.
*
* Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
*
* Tokens start existing when they are minted (`_mint`),
* and stop existing when they are burned (`_burn`).
*/
function _exists(uint256 tokenId) internal view virtual returns (bool) {
return _tokenOwners.contains(tokenId);
}
/**
* @dev Returns whether `spender` is allowed to manage `tokenId`.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
require(_exists(tokenId), "ERC721: operator query for nonexistent token");
address owner = ERC721.ownerOf(tokenId);
return (spender == owner || getApproved(tokenId) == spender || ERC721.isApprovedForAll(owner, spender));
}
/**
* @dev Safely mints `tokenId` and transfers it to `to`.
*
* Requirements:
d*
* - `tokenId` must not exist.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function _safeMint(address to, uint256 tokenId) internal virtual {
_safeMint(to, tokenId, "");
}
/**
* @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
* forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
*/
function _safeMint(address to, uint256 tokenId, bytes memory _data) internal virtual {
_mint(to, tokenId);
require(_checkOnERC721Received(address(0), to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
}
/**
* @dev Mints `tokenId` and transfers it to `to`.
*
* WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
*
* Requirements:
*
* - `tokenId` must not exist.
* - `to` cannot be the zero address.
*
* Emits a {Transfer} event.
*/
function _mint(address to, uint256 tokenId) internal virtual {
require(to != address(0), "ERC721: mint to the zero address");
require(!_exists(tokenId), "ERC721: token already minted");
_beforeTokenTransfer(address(0), to, tokenId);
_holderTokens[to].add(tokenId);
_tokenOwners.set(tokenId, to);
emit Transfer(address(0), to, tokenId);
}
/**
* @dev Destroys `tokenId`.
* The approval is cleared when the token is burned.
*
* Requirements:
*
* - `tokenId` must exist.
*
* Emits a {Transfer} event.
*/
function _burn(uint256 tokenId) internal virtual {
address owner = ERC721.ownerOf(tokenId); // internal owner
_beforeTokenTransfer(owner, address(0), tokenId);
// Clear approvals
_approve(address(0), tokenId);
// Clear metadata (if any)
if (bytes(_tokenURIs[tokenId]).length != 0) {
delete _tokenURIs[tokenId];
}
_holderTokens[owner].remove(tokenId);
_tokenOwners.remove(tokenId);
emit Transfer(owner, address(0), tokenId);
}
/**
* @dev Transfers `tokenId` from `from` to `to`.
* As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
*
* Emits a {Transfer} event.
*/
function _transfer(address from, address to, uint256 tokenId) internal virtual {
require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own"); // internal owner
require(to != address(0), "ERC721: transfer to the zero address");
_beforeTokenTransfer(from, to, tokenId);
// Clear approvals from the previous owner
_approve(address(0), tokenId);
_holderTokens[from].remove(tokenId);
_holderTokens[to].add(tokenId);
_tokenOwners.set(tokenId, to);
emit Transfer(from, to, tokenId);
}
/**
* @dev Sets `_tokenURI` as the tokenURI of `tokenId`.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function _setTokenURI(uint256 tokenId, string memory _tokenURI) internal virtual {
require(_exists(tokenId), "ERC721Metadata: URI set of nonexistent token");
_tokenURIs[tokenId] = _tokenURI;
}
/**
* @dev Internal function to set the base URI for all token IDs. It is
* automatically added as a prefix to the value returned in {tokenURI},
* or to the token ID if {tokenURI} is empty.
*/
function _setBaseURI(string memory baseURI_) internal virtual {
_baseURI = baseURI_;
}
/**
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
* The call is not executed if the target address is not a contract.
*
* @param from address representing the previous owner of the given token ID
* @param to target address that will receive the tokens
* @param tokenId uint256 ID of the token to be transferred
* @param _data bytes optional data to send along with the call
* @return bool whether the call correctly returned the expected magic value
*/
function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory _data)
private returns (bool)
{
if (!to.isContract()) {
return true;
}
bytes memory returndata = to.functionCall(abi.encodeWithSelector(
IERC721Receiver(to).onERC721Received.selector,
_msgSender(),
from,
tokenId,
_data
), "ERC721: transfer to non ERC721Receiver implementer");
bytes4 retval = abi.decode(returndata, (bytes4));
return (retval == _ERC721_RECEIVED);
}
/**
* @dev Approve `to` to operate on `tokenId`
*
* Emits an {Approval} event.
*/
function _approve(address to, uint256 tokenId) internal virtual {
_tokenApprovals[tokenId] = to;
emit Approval(ERC721.ownerOf(tokenId), to, tokenId); // internal owner
}
/**
* @dev Hook that is called before any token transfer. This includes minting
* and burning.
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
* transferred to `to`.
* - When `from` is zero, `tokenId` will be minted for `to`.
* - When `to` is zero, ``from``'s `tokenId` will be burned.
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual { }
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.2 <0.8.0;
import "../../introspection/IERC165.sol";
/**
* @dev Required interface of an ERC721 compliant contract.
*/
interface IERC721 is IERC165 {
/**
* @dev Emitted when `tokenId` token is transferred from `from` to `to`.
*/
event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
/**
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
*/
event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
/**
* @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
*/
event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
/**
* @dev Returns the number of tokens in ``owner``'s account.
*/
function balanceOf(address owner) external view returns (uint256 balance);
/**
* @dev Returns the owner of the `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function ownerOf(uint256 tokenId) external view returns (address owner);
/**
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
* are aware of the ERC721 protocol to prevent tokens from being forever locked.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(address from, address to, uint256 tokenId) external;
/**
* @dev Transfers `tokenId` token from `from` to `to`.
*
* WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
*
* Emits a {Transfer} event.
*/
function transferFrom(address from, address to, uint256 tokenId) external;
/**
* @dev Gives permission to `to` to transfer `tokenId` token to another account.
* The approval is cleared when the token is transferred.
*
* Only a single account can be approved at a time, so approving the zero address clears previous approvals.
*
* Requirements:
*
* - The caller must own the token or be an approved operator.
* - `tokenId` must exist.
*
* Emits an {Approval} event.
*/
function approve(address to, uint256 tokenId) external;
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function getApproved(uint256 tokenId) external view returns (address operator);
/**
* @dev Approve or remove `operator` as an operator for the caller.
* Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
*
* Requirements:
*
* - The `operator` cannot be the caller.
*
* Emits an {ApprovalForAll} event.
*/
function setApprovalForAll(address operator, bool _approved) external;
/**
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}
*/
function isApprovedForAll(address owner, address operator) external view returns (bool);
/**
* @dev Safely transfers `tokenId` token from `from` to `to`.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.2 <0.8.0;
import "./IERC721.sol";
/**
* @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
* @dev See https://eips.ethereum.org/EIPS/eip-721
*/
interface IERC721Enumerable is IERC721 {
/**
* @dev Returns the total amount of tokens stored by the contract.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns a token ID owned by `owner` at a given `index` of its token list.
* Use along with {balanceOf} to enumerate all of ``owner``'s tokens.
*/
function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);
/**
* @dev Returns a token ID at a given `index` of all the tokens stored by the contract.
* Use along with {totalSupply} to enumerate all tokens.
*/
function tokenByIndex(uint256 index) external view returns (uint256);
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.2 <0.8.0;
import "./IERC721.sol";
/**
* @title ERC-721 Non-Fungible Token Standard, optional metadata extension
* @dev See https://eips.ethereum.org/EIPS/eip-721
*/
interface IERC721Metadata is IERC721 {
/**
* @dev Returns the token collection name.
*/
function name() external view returns (string memory);
/**
* @dev Returns the token collection symbol.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
*/
function tokenURI(uint256 tokenId) external view returns (string memory);
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @title ERC721 token receiver interface
* @dev Interface for any contract that wants to support safeTransfers
* from ERC721 asset contracts.
*/
interface IERC721Receiver {
/**
* @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
* by `operator` from `from`, this function is called.
*
* It must return its Solidity selector to confirm the token transfer.
* If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
*
* The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
*/
function onERC721Received(address operator, address from, uint256 tokenId, bytes calldata data) external returns (bytes4);
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.2 <0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
// solhint-disable-next-line no-inline-assembly
assembly { size := extcodesize(account) }
return size > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.delegatecall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Library for managing an enumerable variant of Solidity's
* https://solidity.readthedocs.io/en/latest/types.html#mapping-types[`mapping`]
* type.
*
* Maps have the following properties:
*
* - Entries are added, removed, and checked for existence in constant time
* (O(1)).
* - Entries are enumerated in O(n). No guarantees are made on the ordering.
*
* ```
* contract Example {
* // Add the library methods
* using EnumerableMap for EnumerableMap.UintToAddressMap;
*
* // Declare a set state variable
* EnumerableMap.UintToAddressMap private myMap;
* }
* ```
*
* As of v3.0.0, only maps of type `uint256 -> address` (`UintToAddressMap`) are
* supported.
*/
library EnumerableMap {
// To implement this library for multiple types with as little code
// repetition as possible, we write it in terms of a generic Map type with
// bytes32 keys and values.
// The Map implementation uses private functions, and user-facing
// implementations (such as Uint256ToAddressMap) are just wrappers around
// the underlying Map.
// This means that we can only create new EnumerableMaps for types that fit
// in bytes32.
struct MapEntry {
bytes32 _key;
bytes32 _value;
}
struct Map {
// Storage of map keys and values
MapEntry[] _entries;
// Position of the entry defined by a key in the `entries` array, plus 1
// because index 0 means a key is not in the map.
mapping (bytes32 => uint256) _indexes;
}
/**
* @dev Adds a key-value pair to a map, or updates the value for an existing
* key. O(1).
*
* Returns true if the key was added to the map, that is if it was not
* already present.
*/
function _set(Map storage map, bytes32 key, bytes32 value) private returns (bool) {
// We read and store the key's index to prevent multiple reads from the same storage slot
uint256 keyIndex = map._indexes[key];
if (keyIndex == 0) { // Equivalent to !contains(map, key)
map._entries.push(MapEntry({ _key: key, _value: value }));
// The entry is stored at length-1, but we add 1 to all indexes
// and use 0 as a sentinel value
map._indexes[key] = map._entries.length;
return true;
} else {
map._entries[keyIndex - 1]._value = value;
return false;
}
}
/**
* @dev Removes a key-value pair from a map. O(1).
*
* Returns true if the key was removed from the map, that is if it was present.
*/
function _remove(Map storage map, bytes32 key) private returns (bool) {
// We read and store the key's index to prevent multiple reads from the same storage slot
uint256 keyIndex = map._indexes[key];
if (keyIndex != 0) { // Equivalent to contains(map, key)
// To delete a key-value pair from the _entries array in O(1), we swap the entry to delete with the last one
// in the array, and then remove the last entry (sometimes called as 'swap and pop').
// This modifies the order of the array, as noted in {at}.
uint256 toDeleteIndex = keyIndex - 1;
uint256 lastIndex = map._entries.length - 1;
// When the entry to delete is the last one, the swap operation is unnecessary. However, since this occurs
// so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.
MapEntry storage lastEntry = map._entries[lastIndex];
// Move the last entry to the index where the entry to delete is
map._entries[toDeleteIndex] = lastEntry;
// Update the index for the moved entry
map._indexes[lastEntry._key] = toDeleteIndex + 1; // All indexes are 1-based
// Delete the slot where the moved entry was stored
map._entries.pop();
// Delete the index for the deleted slot
delete map._indexes[key];
return true;
} else {
return false;
}
}
/**
* @dev Returns true if the key is in the map. O(1).
*/
function _contains(Map storage map, bytes32 key) private view returns (bool) {
return map._indexes[key] != 0;
}
/**
* @dev Returns the number of key-value pairs in the map. O(1).
*/
function _length(Map storage map) private view returns (uint256) {
return map._entries.length;
}
/**
* @dev Returns the key-value pair stored at position `index` in the map. O(1).
*
* Note that there are no guarantees on the ordering of entries inside the
* array, and it may change when more entries are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/
function _at(Map storage map, uint256 index) private view returns (bytes32, bytes32) {
require(map._entries.length > index, "EnumerableMap: index out of bounds");
MapEntry storage entry = map._entries[index];
return (entry._key, entry._value);
}
/**
* @dev Tries to returns the value associated with `key`. O(1).
* Does not revert if `key` is not in the map.
*/
function _tryGet(Map storage map, bytes32 key) private view returns (bool, bytes32) {
uint256 keyIndex = map._indexes[key];
if (keyIndex == 0) return (false, 0); // Equivalent to contains(map, key)
return (true, map._entries[keyIndex - 1]._value); // All indexes are 1-based
}
/**
* @dev Returns the value associated with `key`. O(1).
*
* Requirements:
*
* - `key` must be in the map.
*/
function _get(Map storage map, bytes32 key) private view returns (bytes32) {
uint256 keyIndex = map._indexes[key];
require(keyIndex != 0, "EnumerableMap: nonexistent key"); // Equivalent to contains(map, key)
return map._entries[keyIndex - 1]._value; // All indexes are 1-based
}
/**
* @dev Same as {_get}, with a custom error message when `key` is not in the map.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {_tryGet}.
*/
function _get(Map storage map, bytes32 key, string memory errorMessage) private view returns (bytes32) {
uint256 keyIndex = map._indexes[key];
require(keyIndex != 0, errorMessage); // Equivalent to contains(map, key)
return map._entries[keyIndex - 1]._value; // All indexes are 1-based
}
// UintToAddressMap
struct UintToAddressMap {
Map _inner;
}
/**
* @dev Adds a key-value pair to a map, or updates the value for an existing
* key. O(1).
*
* Returns true if the key was added to the map, that is if it was not
* already present.
*/
function set(UintToAddressMap storage map, uint256 key, address value) internal returns (bool) {
return _set(map._inner, bytes32(key), bytes32(uint256(uint160(value))));
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the key was removed from the map, that is if it was present.
*/
function remove(UintToAddressMap storage map, uint256 key) internal returns (bool) {
return _remove(map._inner, bytes32(key));
}
/**
* @dev Returns true if the key is in the map. O(1).
*/
function contains(UintToAddressMap storage map, uint256 key) internal view returns (bool) {
return _contains(map._inner, bytes32(key));
}
/**
* @dev Returns the number of elements in the map. O(1).
*/
function length(UintToAddressMap storage map) internal view returns (uint256) {
return _length(map._inner);
}
/**
* @dev Returns the element stored at position `index` in the set. O(1).
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/
function at(UintToAddressMap storage map, uint256 index) internal view returns (uint256, address) {
(bytes32 key, bytes32 value) = _at(map._inner, index);
return (uint256(key), address(uint160(uint256(value))));
}
/**
* @dev Tries to returns the value associated with `key`. O(1).
* Does not revert if `key` is not in the map.
*
* _Available since v3.4._
*/
function tryGet(UintToAddressMap storage map, uint256 key) internal view returns (bool, address) {
(bool success, bytes32 value) = _tryGet(map._inner, bytes32(key));
return (success, address(uint160(uint256(value))));
}
/**
* @dev Returns the value associated with `key`. O(1).
*
* Requirements:
*
* - `key` must be in the map.
*/
function get(UintToAddressMap storage map, uint256 key) internal view returns (address) {
return address(uint160(uint256(_get(map._inner, bytes32(key)))));
}
/**
* @dev Same as {get}, with a custom error message when `key` is not in the map.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryGet}.
*/
function get(UintToAddressMap storage map, uint256 key, string memory errorMessage) internal view returns (address) {
return address(uint160(uint256(_get(map._inner, bytes32(key), errorMessage))));
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Library for managing
* https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
* types.
*
* Sets have the following properties:
*
* - Elements are added, removed, and checked for existence in constant time
* (O(1)).
* - Elements are enumerated in O(n). No guarantees are made on the ordering.
*
* ```
* contract Example {
* // Add the library methods
* using EnumerableSet for EnumerableSet.AddressSet;
*
* // Declare a set state variable
* EnumerableSet.AddressSet private mySet;
* }
* ```
*
* As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
* and `uint256` (`UintSet`) are supported.
*/
library EnumerableSet {
// To implement this library for multiple types with as little code
// repetition as possible, we write it in terms of a generic Set type with
// bytes32 values.
// The Set implementation uses private functions, and user-facing
// implementations (such as AddressSet) are just wrappers around the
// underlying Set.
// This means that we can only create new EnumerableSets for types that fit
// in bytes32.
struct Set {
// Storage of set values
bytes32[] _values;
// Position of the value in the `values` array, plus 1 because index 0
// means a value is not in the set.
mapping (bytes32 => uint256) _indexes;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/
function _add(Set storage set, bytes32 value) private returns (bool) {
if (!_contains(set, value)) {
set._values.push(value);
// The value is stored at length-1, but we add 1 to all indexes
// and use 0 as a sentinel value
set._indexes[value] = set._values.length;
return true;
} else {
return false;
}
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/
function _remove(Set storage set, bytes32 value) private returns (bool) {
// We read and store the value's index to prevent multiple reads from the same storage slot
uint256 valueIndex = set._indexes[value];
if (valueIndex != 0) { // Equivalent to contains(set, value)
// To delete an element from the _values array in O(1), we swap the element to delete with the last one in
// the array, and then remove the last element (sometimes called as 'swap and pop').
// This modifies the order of the array, as noted in {at}.
uint256 toDeleteIndex = valueIndex - 1;
uint256 lastIndex = set._values.length - 1;
// When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
// so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.
bytes32 lastvalue = set._values[lastIndex];
// Move the last value to the index where the value to delete is
set._values[toDeleteIndex] = lastvalue;
// Update the index for the moved value
set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based
// Delete the slot where the moved value was stored
set._values.pop();
// Delete the index for the deleted slot
delete set._indexes[value];
return true;
} else {
return false;
}
}
/**
* @dev Returns true if the value is in the set. O(1).
*/
function _contains(Set storage set, bytes32 value) private view returns (bool) {
return set._indexes[value] != 0;
}
/**
* @dev Returns the number of values on the set. O(1).
*/
function _length(Set storage set) private view returns (uint256) {
return set._values.length;
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/
function _at(Set storage set, uint256 index) private view returns (bytes32) {
require(set._values.length > index, "EnumerableSet: index out of bounds");
return set._values[index];
}
// Bytes32Set
struct Bytes32Set {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/
function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
return _add(set._inner, value);
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/
function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
return _remove(set._inner, value);
}
/**
* @dev Returns true if the value is in the set. O(1).
*/
function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
return _contains(set._inner, value);
}
/**
* @dev Returns the number of values in the set. O(1).
*/
function length(Bytes32Set storage set) internal view returns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/
function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
return _at(set._inner, index);
}
// AddressSet
struct AddressSet {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/
function add(AddressSet storage set, address value) internal returns (bool) {
return _add(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/
function remove(AddressSet storage set, address value) internal returns (bool) {
return _remove(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Returns true if the value is in the set. O(1).
*/
function contains(AddressSet storage set, address value) internal view returns (bool) {
return _contains(set._inner, bytes32(uint256(uint160(value))));
}
/**
* @dev Returns the number of values in the set. O(1).
*/
function length(AddressSet storage set) internal view returns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/
function at(AddressSet storage set, uint256 index) internal view returns (address) {
return address(uint160(uint256(_at(set._inner, index))));
}
// UintSet
struct UintSet {
Set _inner;
}
/**
* @dev Add a value to a set. O(1).
*
* Returns true if the value was added to the set, that is if it was not
* already present.
*/
function add(UintSet storage set, uint256 value) internal returns (bool) {
return _add(set._inner, bytes32(value));
}
/**
* @dev Removes a value from a set. O(1).
*
* Returns true if the value was removed from the set, that is if it was
* present.
*/
function remove(UintSet storage set, uint256 value) internal returns (bool) {
return _remove(set._inner, bytes32(value));
}
/**
* @dev Returns true if the value is in the set. O(1).
*/
function contains(UintSet storage set, uint256 value) internal view returns (bool) {
return _contains(set._inner, bytes32(value));
}
/**
* @dev Returns the number of values on the set. O(1).
*/
function length(UintSet storage set) internal view returns (uint256) {
return _length(set._inner);
}
/**
* @dev Returns the value stored at position `index` in the set. O(1).
*
* Note that there are no guarantees on the ordering of values inside the
* array, and it may change when more values are added or removed.
*
* Requirements:
*
* - `index` must be strictly less than {length}.
*/
function at(UintSet storage set, uint256 index) internal view returns (uint256) {
return uint256(_at(set._inner, index));
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev String operations.
*/
library Strings {
/**
* @dev Converts a `uint256` to its ASCII `string` representation.
*/
function toString(uint256 value) internal pure returns (string memory) {
// Inspired by OraclizeAPI's implementation - MIT licence
// https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
if (value == 0) {
return "0";
}
uint256 temp = value;
uint256 digits;
while (temp != 0) {
digits++;
temp /= 10;
}
bytes memory buffer = new bytes(digits);
uint256 index = digits - 1;
temp = value;
while (temp != 0) {
buffer[index--] = bytes1(uint8(48 + temp % 10));
temp /= 10;
}
return string(buffer);
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/proxy/Clones.sol";
import "synthetix/contracts/interfaces/IAddressResolver.sol";
import "synthetix/contracts/interfaces/IExchanger.sol";
import "synthetix/contracts/interfaces/IExchangeRates.sol";
import "../interfaces/ISwap.sol";
import "./SynthSwapper.sol";
contract Proxy {
address public target;
}
contract Target {
address public proxy;
}
/**
* @title Bridge
* @notice This contract is responsible for cross-asset swaps using the Synthetix protocol as the bridging exchange.
* There are three types of supported cross-asset swaps, tokenToSynth, synthToToken, and tokenToToken.
*
* 1) tokenToSynth
* Swaps a supported token in a saddle pool to any synthetic asset (e.g. tBTC -> sAAVE).
*
* 2) synthToToken
* Swaps any synthetic asset to a suported token in a saddle pool (e.g. sDEFI -> USDC).
*
* 3) tokenToToken
* Swaps a supported token in a saddle pool to one in another pool (e.g. renBTC -> DAI).
*
* Due to the settlement periods of synthetic assets, the users must wait until the trades can be completed.
* Users will receive an ERC721 token that represents pending cross-asset swap. Once the waiting period is over,
* the trades can be settled and completed by calling the `completeToSynth` or the `completeToToken` function.
* In the cases of pending `synthToToken` or `tokenToToken` swaps, the owners of the pending swaps can also choose
* to withdraw the bridging synthetic assets instead of completing the swap.
*/
contract Bridge is ERC721 {
using SafeMath for uint256;
using SafeERC20 for IERC20;
event SynthIndex(
address indexed swap,
uint8 synthIndex,
bytes32 currencyKey,
address synthAddress
);
event TokenToSynth(
address indexed requester,
uint256 indexed itemId,
ISwap swapPool,
uint8 tokenFromIndex,
uint256 tokenFromInAmount,
bytes32 synthToKey
);
event SynthToToken(
address indexed requester,
uint256 indexed itemId,
ISwap swapPool,
bytes32 synthFromKey,
uint256 synthFromInAmount,
uint8 tokenToIndex
);
event TokenToToken(
address indexed requester,
uint256 indexed itemId,
ISwap[2] swapPools,
uint8 tokenFromIndex,
uint256 tokenFromAmount,
uint8 tokenToIndex
);
event Settle(
address indexed requester,
uint256 indexed itemId,
IERC20 settleFrom,
uint256 settleFromAmount,
IERC20 settleTo,
uint256 settleToAmount,
bool isFinal
);
event Withdraw(
address indexed requester,
uint256 indexed itemId,
IERC20 synth,
uint256 synthAmount,
bool isFinal
);
// The addresses for all Synthetix contracts can be found in the below URL.
// https://docs.synthetix.io/addresses/#mainnet-contracts
//
// Since the Synthetix protocol is upgradable, we must use the proxy pairs of each contract such that
// the composability is not broken after the protocol upgrade.
//
// SYNTHETIX_RESOLVER points to `ReadProxyAddressResolver` (0x4E3b31eB0E5CB73641EE1E65E7dCEFe520bA3ef2).
// This contract is a read proxy of `AddressResolver` which is responsible for storing the addresses of the contracts
// used by the Synthetix protocol.
IAddressResolver public constant SYNTHETIX_RESOLVER =
IAddressResolver(0x4E3b31eB0E5CB73641EE1E65E7dCEFe520bA3ef2);
// EXCHANGER points to `Exchanger`. There is no proxy pair for this contract so we need to update this variable
// when the protocol is upgraded. This contract is used to settle synths held by SynthSwapper.
IExchanger public exchanger;
// CONSTANTS
// Available types of cross-asset swaps
enum PendingSwapType {
Null,
TokenToSynth,
SynthToToken,
TokenToToken
}
uint256 public constant MAX_UINT256 = 2**256 - 1;
uint8 public constant MAX_UINT8 = 2**8 - 1;
bytes32 public constant EXCHANGE_RATES_NAME = "ExchangeRates";
bytes32 public constant EXCHANGER_NAME = "Exchanger";
address public immutable SYNTH_SWAPPER_MASTER;
// MAPPINGS FOR STORING PENDING SETTLEMENTS
// The below two mappings never share the same key.
mapping(uint256 => PendingToSynthSwap) public pendingToSynthSwaps;
mapping(uint256 => PendingToTokenSwap) public pendingToTokenSwaps;
uint256 public pendingSwapsLength;
mapping(uint256 => PendingSwapType) private pendingSwapType;
// MAPPINGS FOR STORING SYNTH INFO
mapping(address => SwapContractInfo) private swapContracts;
// Structs holding information about pending settlements
struct PendingToSynthSwap {
SynthSwapper swapper;
bytes32 synthKey;
}
struct PendingToTokenSwap {
SynthSwapper swapper;
bytes32 synthKey;
ISwap swap;
uint8 tokenToIndex;
}
struct SwapContractInfo {
// index of the supported synth + 1
uint8 synthIndexPlusOne;
// address of the supported synth
address synthAddress;
// bytes32 key of the supported synth
bytes32 synthKey;
// array of tokens supported by the contract
IERC20[] tokens;
}
/**
* @notice Deploys this contract and initializes the master version of the SynthSwapper contract. The address to
* the Synthetix protocol's Exchanger contract is also set on deployment.
*/
constructor(address synthSwapperAddress)
public
ERC721("Saddle Cross-Asset Swap", "SaddleSynthSwap")
{
SYNTH_SWAPPER_MASTER = synthSwapperAddress;
updateExchangerCache();
}
/**
* @notice Returns the address of the proxy contract targeting the synthetic asset with the given `synthKey`.
* @param synthKey the currency key of the synth
* @return address of the proxy contract
*/
function getProxyAddressFromTargetSynthKey(bytes32 synthKey)
public
view
returns (IERC20)
{
return IERC20(Target(SYNTHETIX_RESOLVER.getSynth(synthKey)).proxy());
}
/**
* @notice Returns various information of a pending swap represented by the given `itemId`. Information includes
* the type of the pending swap, the number of seconds left until it can be settled, the address and the balance
* of the synth this swap currently holds, and the address of the destination token.
* @param itemId ID of the pending swap
* @return swapType the type of the pending virtual swap,
* secsLeft number of seconds left until this swap can be settled,
* synth address of the synth this swap uses,
* synthBalance amount of the synth this swap holds,
* tokenTo the address of the destination token
*/
function getPendingSwapInfo(uint256 itemId)
external
view
returns (
PendingSwapType swapType,
uint256 secsLeft,
address synth,
uint256 synthBalance,
address tokenTo
)
{
swapType = pendingSwapType[itemId];
require(swapType != PendingSwapType.Null, "invalid itemId");
SynthSwapper synthSwapper;
bytes32 synthKey;
if (swapType == PendingSwapType.TokenToSynth) {
synthSwapper = pendingToSynthSwaps[itemId].swapper;
synthKey = pendingToSynthSwaps[itemId].synthKey;
synth = address(getProxyAddressFromTargetSynthKey(synthKey));
tokenTo = synth;
} else {
PendingToTokenSwap memory pendingToTokenSwap = pendingToTokenSwaps[
itemId
];
synthSwapper = pendingToTokenSwap.swapper;
synthKey = pendingToTokenSwap.synthKey;
synth = address(getProxyAddressFromTargetSynthKey(synthKey));
tokenTo = address(
swapContracts[address(pendingToTokenSwap.swap)].tokens[
pendingToTokenSwap.tokenToIndex
]
);
}
secsLeft = exchanger.maxSecsLeftInWaitingPeriod(
address(synthSwapper),
synthKey
);
synthBalance = IERC20(synth).balanceOf(address(synthSwapper));
}
// Settles the synth only.
function _settle(address synthOwner, bytes32 synthKey) internal {
// Settle synth
exchanger.settle(synthOwner, synthKey);
}
/**
* @notice Settles and withdraws the synthetic asset without swapping it to a token in a Saddle pool. Only the owner
* of the ERC721 token of `itemId` can call this function. Reverts if the given `itemId` does not represent a
* `synthToToken` or a `tokenToToken` swap.
* @param itemId ID of the pending swap
* @param amount the amount of the synth to withdraw
*/
function withdraw(uint256 itemId, uint256 amount) external {
address nftOwner = ownerOf(itemId);
require(nftOwner == msg.sender, "not owner");
require(
pendingSwapType[itemId] > PendingSwapType.TokenToSynth,
"invalid itemId"
);
PendingToTokenSwap memory pendingToTokenSwap = pendingToTokenSwaps[
itemId
];
_settle(
address(pendingToTokenSwap.swapper),
pendingToTokenSwap.synthKey
);
IERC20 synth = getProxyAddressFromTargetSynthKey(
pendingToTokenSwap.synthKey
);
bool shouldDestroy;
if (amount >= synth.balanceOf(address(pendingToTokenSwap.swapper))) {
_burn(itemId);
delete pendingToTokenSwaps[itemId];
delete pendingSwapType[itemId];
shouldDestroy = true;
}
pendingToTokenSwap.swapper.withdraw(
synth,
nftOwner,
amount,
shouldDestroy
);
emit Withdraw(msg.sender, itemId, synth, amount, shouldDestroy);
}
/**
* @notice Completes the pending `tokenToSynth` swap by settling and withdrawing the synthetic asset.
* Reverts if the given `itemId` does not represent a `tokenToSynth` swap.
* @param itemId ERC721 token ID representing a pending `tokenToSynth` swap
*/
function completeToSynth(uint256 itemId) external {
address nftOwner = ownerOf(itemId);
require(nftOwner == msg.sender, "not owner");
require(
pendingSwapType[itemId] == PendingSwapType.TokenToSynth,
"invalid itemId"
);
PendingToSynthSwap memory pendingToSynthSwap = pendingToSynthSwaps[
itemId
];
_settle(
address(pendingToSynthSwap.swapper),
pendingToSynthSwap.synthKey
);
IERC20 synth = getProxyAddressFromTargetSynthKey(
pendingToSynthSwap.synthKey
);
// Burn the corresponding ERC721 token and delete storage for gas
_burn(itemId);
delete pendingToTokenSwaps[itemId];
delete pendingSwapType[itemId];
// After settlement, withdraw the synth and send it to the recipient
uint256 synthBalance = synth.balanceOf(
address(pendingToSynthSwap.swapper)
);
pendingToSynthSwap.swapper.withdraw(
synth,
nftOwner,
synthBalance,
true
);
emit Settle(
msg.sender,
itemId,
synth,
synthBalance,
synth,
synthBalance,
true
);
}
/**
* @notice Calculates the expected amount of the token to receive on calling `completeToToken()` with
* the given `swapAmount`.
* @param itemId ERC721 token ID representing a pending `SynthToToken` or `TokenToToken` swap
* @param swapAmount the amount of bridging synth to swap from
* @return expected amount of the token the user will receive
*/
function calcCompleteToToken(uint256 itemId, uint256 swapAmount)
external
view
returns (uint256)
{
require(
pendingSwapType[itemId] > PendingSwapType.TokenToSynth,
"invalid itemId"
);
PendingToTokenSwap memory pendingToTokenSwap = pendingToTokenSwaps[
itemId
];
return
pendingToTokenSwap.swap.calculateSwap(
getSynthIndex(pendingToTokenSwap.swap),
pendingToTokenSwap.tokenToIndex,
swapAmount
);
}
/**
* @notice Completes the pending `SynthToToken` or `TokenToToken` swap by settling the bridging synth and swapping
* it to the desired token. Only the owners of the pending swaps can call this function.
* @param itemId ERC721 token ID representing a pending `SynthToToken` or `TokenToToken` swap
* @param swapAmount the amount of bridging synth to swap from
* @param minAmount the minimum amount of the token to receive - reverts if this amount is not reached
* @param deadline the timestamp representing the deadline for this transaction - reverts if deadline is not met
*/
function completeToToken(
uint256 itemId,
uint256 swapAmount,
uint256 minAmount,
uint256 deadline
) external {
require(swapAmount != 0, "amount must be greater than 0");
address nftOwner = ownerOf(itemId);
require(msg.sender == nftOwner, "must own itemId");
require(
pendingSwapType[itemId] > PendingSwapType.TokenToSynth,
"invalid itemId"
);
PendingToTokenSwap memory pendingToTokenSwap = pendingToTokenSwaps[
itemId
];
_settle(
address(pendingToTokenSwap.swapper),
pendingToTokenSwap.synthKey
);
IERC20 synth = getProxyAddressFromTargetSynthKey(
pendingToTokenSwap.synthKey
);
bool shouldDestroyClone;
if (
swapAmount >= synth.balanceOf(address(pendingToTokenSwap.swapper))
) {
_burn(itemId);
delete pendingToTokenSwaps[itemId];
delete pendingSwapType[itemId];
shouldDestroyClone = true;
}
// Try swapping the synth to the desired token via the stored swap pool contract
// If the external call succeeds, send the token to the owner of token with itemId.
(IERC20 tokenTo, uint256 amountOut) = pendingToTokenSwap
.swapper
.swapSynthToToken(
pendingToTokenSwap.swap,
synth,
getSynthIndex(pendingToTokenSwap.swap),
pendingToTokenSwap.tokenToIndex,
swapAmount,
minAmount,
deadline,
nftOwner
);
if (shouldDestroyClone) {
pendingToTokenSwap.swapper.destroy();
}
emit Settle(
msg.sender,
itemId,
synth,
swapAmount,
tokenTo,
amountOut,
shouldDestroyClone
);
}
// Add the given pending synth settlement struct to the list
function _addToPendingSynthSwapList(
PendingToSynthSwap memory pendingToSynthSwap
) internal returns (uint256) {
require(
pendingSwapsLength < MAX_UINT256,
"pendingSwapsLength reached max size"
);
pendingToSynthSwaps[pendingSwapsLength] = pendingToSynthSwap;
return pendingSwapsLength++;
}
// Add the given pending synth to token settlement struct to the list
function _addToPendingSynthToTokenSwapList(
PendingToTokenSwap memory pendingToTokenSwap
) internal returns (uint256) {
require(
pendingSwapsLength < MAX_UINT256,
"pendingSwapsLength reached max size"
);
pendingToTokenSwaps[pendingSwapsLength] = pendingToTokenSwap;
return pendingSwapsLength++;
}
/**
* @notice Calculates the expected amount of the desired synthetic asset the caller will receive after completing
* a `TokenToSynth` swap with the given parameters. This calculation does not consider the settlement periods.
* @param swap the address of a Saddle pool to use to swap the given token to a bridging synth
* @param tokenFromIndex the index of the token to swap from
* @param synthOutKey the currency key of the desired synthetic asset
* @param tokenInAmount the amount of the token to swap form
* @return the expected amount of the desired synth
*/
function calcTokenToSynth(
ISwap swap,
uint8 tokenFromIndex,
bytes32 synthOutKey,
uint256 tokenInAmount
) external view returns (uint256) {
uint8 mediumSynthIndex = getSynthIndex(swap);
uint256 expectedMediumSynthAmount = swap.calculateSwap(
tokenFromIndex,
mediumSynthIndex,
tokenInAmount
);
bytes32 mediumSynthKey = getSynthKey(swap);
IExchangeRates exchangeRates = IExchangeRates(
SYNTHETIX_RESOLVER.getAddress(EXCHANGE_RATES_NAME)
);
return
exchangeRates.effectiveValue(
mediumSynthKey,
expectedMediumSynthAmount,
synthOutKey
);
}
/**
* @notice Initiates a cross-asset swap from a token supported in the `swap` pool to any synthetic asset.
* The caller will receive an ERC721 token representing their ownership of the pending cross-asset swap.
* @param swap the address of a Saddle pool to use to swap the given token to a bridging synth
* @param tokenFromIndex the index of the token to swap from
* @param synthOutKey the currency key of the desired synthetic asset
* @param tokenInAmount the amount of the token to swap form
* @param minAmount the amount of the token to swap form
* @return ID of the ERC721 token sent to the caller
*/
function tokenToSynth(
ISwap swap,
uint8 tokenFromIndex,
bytes32 synthOutKey,
uint256 tokenInAmount,
uint256 minAmount
) external returns (uint256) {
require(tokenInAmount != 0, "amount must be greater than 0");
// Create a SynthSwapper clone
SynthSwapper synthSwapper = SynthSwapper(
Clones.clone(SYNTH_SWAPPER_MASTER)
);
synthSwapper.initialize();
// Add the synthswapper to the pending settlement list
uint256 itemId = _addToPendingSynthSwapList(
PendingToSynthSwap(synthSwapper, synthOutKey)
);
pendingSwapType[itemId] = PendingSwapType.TokenToSynth;
// Mint an ERC721 token that represents ownership of the pending synth settlement to msg.sender
_mint(msg.sender, itemId);
// Transfer token from msg.sender
IERC20 tokenFrom = swapContracts[address(swap)].tokens[tokenFromIndex]; // revert when token not found in swap pool
tokenFrom.safeTransferFrom(msg.sender, address(this), tokenInAmount);
tokenInAmount = tokenFrom.balanceOf(address(this));
// Swap the synth to the medium synth
uint256 mediumSynthAmount = swap.swap(
tokenFromIndex,
getSynthIndex(swap),
tokenInAmount,
0,
block.timestamp
);
// Swap synths via Synthetix network
IERC20(getSynthAddress(swap)).safeTransfer(
address(synthSwapper),
mediumSynthAmount
);
require(
synthSwapper.swapSynth(
getSynthKey(swap),
mediumSynthAmount,
synthOutKey
) >= minAmount,
"minAmount not reached"
);
// Emit TokenToSynth event with relevant data
emit TokenToSynth(
msg.sender,
itemId,
swap,
tokenFromIndex,
tokenInAmount,
synthOutKey
);
return (itemId);
}
/**
* @notice Calculates the expected amount of the desired token the caller will receive after completing
* a `SynthToToken` swap with the given parameters. This calculation does not consider the settlement periods or
* any potential changes of the `swap` pool composition.
* @param swap the address of a Saddle pool to use to swap the given token to a bridging synth
* @param synthInKey the currency key of the synth to swap from
* @param tokenToIndex the index of the token to swap to
* @param synthInAmount the amount of the synth to swap form
* @return the expected amount of the bridging synth and the expected amount of the desired token
*/
function calcSynthToToken(
ISwap swap,
bytes32 synthInKey,
uint8 tokenToIndex,
uint256 synthInAmount
) external view returns (uint256, uint256) {
IExchangeRates exchangeRates = IExchangeRates(
SYNTHETIX_RESOLVER.getAddress(EXCHANGE_RATES_NAME)
);
uint8 mediumSynthIndex = getSynthIndex(swap);
bytes32 mediumSynthKey = getSynthKey(swap);
require(synthInKey != mediumSynthKey, "use normal swap");
uint256 expectedMediumSynthAmount = exchangeRates.effectiveValue(
synthInKey,
synthInAmount,
mediumSynthKey
);
return (
expectedMediumSynthAmount,
swap.calculateSwap(
mediumSynthIndex,
tokenToIndex,
expectedMediumSynthAmount
)
);
}
/**
* @notice Initiates a cross-asset swap from a synthetic asset to a supported token. The caller will receive
* an ERC721 token representing their ownership of the pending cross-asset swap.
* @param swap the address of a Saddle pool to use to swap the given token to a bridging synth
* @param synthInKey the currency key of the synth to swap from
* @param tokenToIndex the index of the token to swap to
* @param synthInAmount the amount of the synth to swap form
* @param minMediumSynthAmount the minimum amount of the bridging synth at pre-settlement stage
* @return the ID of the ERC721 token sent to the caller
*/
function synthToToken(
ISwap swap,
bytes32 synthInKey,
uint8 tokenToIndex,
uint256 synthInAmount,
uint256 minMediumSynthAmount
) external returns (uint256) {
require(synthInAmount != 0, "amount must be greater than 0");
bytes32 mediumSynthKey = getSynthKey(swap);
require(
synthInKey != mediumSynthKey,
"synth is supported via normal swap"
);
// Create a SynthSwapper clone
SynthSwapper synthSwapper = SynthSwapper(
Clones.clone(SYNTH_SWAPPER_MASTER)
);
synthSwapper.initialize();
// Add the synthswapper to the pending synth to token settlement list
uint256 itemId = _addToPendingSynthToTokenSwapList(
PendingToTokenSwap(synthSwapper, mediumSynthKey, swap, tokenToIndex)
);
pendingSwapType[itemId] = PendingSwapType.SynthToToken;
// Mint an ERC721 token that represents ownership of the pending synth to token settlement to msg.sender
_mint(msg.sender, itemId);
// Receive synth from the user and swap it to another synth
IERC20 synthFrom = getProxyAddressFromTargetSynthKey(synthInKey);
synthFrom.safeTransferFrom(msg.sender, address(this), synthInAmount);
synthFrom.safeTransfer(address(synthSwapper), synthInAmount);
require(
synthSwapper.swapSynth(synthInKey, synthInAmount, mediumSynthKey) >=
minMediumSynthAmount,
"minMediumSynthAmount not reached"
);
// Emit SynthToToken event with relevant data
emit SynthToToken(
msg.sender,
itemId,
swap,
synthInKey,
synthInAmount,
tokenToIndex
);
return (itemId);
}
/**
* @notice Calculates the expected amount of the desired token the caller will receive after completing
* a `TokenToToken` swap with the given parameters. This calculation does not consider the settlement periods or
* any potential changes of the pool compositions.
* @param swaps the addresses of the two Saddle pools used to do the cross-asset swap
* @param tokenFromIndex the index of the token in the first `swaps` pool to swap from
* @param tokenToIndex the index of the token in the second `swaps` pool to swap to
* @param tokenFromAmount the amount of the token to swap from
* @return the expected amount of bridging synth at pre-settlement stage and the expected amount of the desired
* token
*/
function calcTokenToToken(
ISwap[2] calldata swaps,
uint8 tokenFromIndex,
uint8 tokenToIndex,
uint256 tokenFromAmount
) external view returns (uint256, uint256) {
IExchangeRates exchangeRates = IExchangeRates(
SYNTHETIX_RESOLVER.getAddress(EXCHANGE_RATES_NAME)
);
uint256 firstSynthAmount = swaps[0].calculateSwap(
tokenFromIndex,
getSynthIndex(swaps[0]),
tokenFromAmount
);
uint256 mediumSynthAmount = exchangeRates.effectiveValue(
getSynthKey(swaps[0]),
firstSynthAmount,
getSynthKey(swaps[1])
);
return (
mediumSynthAmount,
swaps[1].calculateSwap(
getSynthIndex(swaps[1]),
tokenToIndex,
mediumSynthAmount
)
);
}
/**
* @notice Initiates a cross-asset swap from a token in one Saddle pool to one in another. The caller will receive
* an ERC721 token representing their ownership of the pending cross-asset swap.
* @param swaps the addresses of the two Saddle pools used to do the cross-asset swap
* @param tokenFromIndex the index of the token in the first `swaps` pool to swap from
* @param tokenToIndex the index of the token in the second `swaps` pool to swap to
* @param tokenFromAmount the amount of the token to swap from
* @param minMediumSynthAmount the minimum amount of the bridging synth at pre-settlement stage
* @return the ID of the ERC721 token sent to the caller
*/
function tokenToToken(
ISwap[2] calldata swaps,
uint8 tokenFromIndex,
uint8 tokenToIndex,
uint256 tokenFromAmount,
uint256 minMediumSynthAmount
) external returns (uint256) {
// Create a SynthSwapper clone
require(tokenFromAmount != 0, "amount must be greater than 0");
SynthSwapper synthSwapper = SynthSwapper(
Clones.clone(SYNTH_SWAPPER_MASTER)
);
synthSwapper.initialize();
bytes32 mediumSynthKey = getSynthKey(swaps[1]);
// Add the synthswapper to the pending synth to token settlement list
uint256 itemId = _addToPendingSynthToTokenSwapList(
PendingToTokenSwap(
synthSwapper,
mediumSynthKey,
swaps[1],
tokenToIndex
)
);
pendingSwapType[itemId] = PendingSwapType.TokenToToken;
// Mint an ERC721 token that represents ownership of the pending swap to msg.sender
_mint(msg.sender, itemId);
// Receive token from the user
ISwap swap = swaps[0];
{
IERC20 tokenFrom = swapContracts[address(swap)].tokens[
tokenFromIndex
];
tokenFrom.safeTransferFrom(
msg.sender,
address(this),
tokenFromAmount
);
}
uint256 firstSynthAmount = swap.swap(
tokenFromIndex,
getSynthIndex(swap),
tokenFromAmount,
0,
block.timestamp
);
// Swap the synth to another synth
IERC20(getSynthAddress(swap)).safeTransfer(
address(synthSwapper),
firstSynthAmount
);
require(
synthSwapper.swapSynth(
getSynthKey(swap),
firstSynthAmount,
mediumSynthKey
) >= minMediumSynthAmount,
"minMediumSynthAmount not reached"
);
// Emit TokenToToken event with relevant data
emit TokenToToken(
msg.sender,
itemId,
swaps,
tokenFromIndex,
tokenFromAmount,
tokenToIndex
);
return (itemId);
}
/**
* @notice Registers the index and the address of the supported synth from the given `swap` pool. The matching currency key must
* be supplied for a successful registration.
* @param swap the address of the pool that contains the synth
* @param synthIndex the index of the supported synth in the given `swap` pool
* @param currencyKey the currency key of the synth in bytes32 form
*/
function setSynthIndex(
ISwap swap,
uint8 synthIndex,
bytes32 currencyKey
) external {
require(synthIndex < MAX_UINT8, "index is too large");
SwapContractInfo storage swapContractInfo = swapContracts[
address(swap)
];
// Check if the pool has already been added
require(swapContractInfo.synthIndexPlusOne == 0, "Pool already added");
// Ensure the synth with the same currency key exists at the given `synthIndex`
IERC20 synth = swap.getToken(synthIndex);
require(
ISynth(Proxy(address(synth)).target()).currencyKey() == currencyKey,
"currencyKey does not match"
);
swapContractInfo.synthIndexPlusOne = synthIndex + 1;
swapContractInfo.synthAddress = address(synth);
swapContractInfo.synthKey = currencyKey;
swapContractInfo.tokens = new IERC20[](0);
for (uint8 i = 0; i < MAX_UINT8; i++) {
IERC20 token;
if (i == synthIndex) {
token = synth;
} else {
try swap.getToken(i) returns (IERC20 token_) {
token = token_;
} catch {
break;
}
}
swapContractInfo.tokens.push(token);
token.safeApprove(address(swap), MAX_UINT256);
}
emit SynthIndex(address(swap), synthIndex, currencyKey, address(synth));
}
/**
* @notice Returns the index of the supported synth in the given `swap` pool. Reverts if the `swap` pool
* is not registered.
* @param swap the address of the pool that contains the synth
* @return the index of the supported synth
*/
function getSynthIndex(ISwap swap) public view returns (uint8) {
uint8 synthIndexPlusOne = swapContracts[address(swap)]
.synthIndexPlusOne;
require(synthIndexPlusOne > 0, "synth index not found for given pool");
return synthIndexPlusOne - 1;
}
/**
* @notice Returns the address of the supported synth in the given `swap` pool. Reverts if the `swap` pool
* is not registered.
* @param swap the address of the pool that contains the synth
* @return the address of the supported synth
*/
function getSynthAddress(ISwap swap) public view returns (address) {
address synthAddress = swapContracts[address(swap)].synthAddress;
require(
synthAddress != address(0),
"synth addr not found for given pool"
);
return synthAddress;
}
/**
* @notice Returns the currency key of the supported synth in the given `swap` pool. Reverts if the `swap` pool
* is not registered.
* @param swap the address of the pool that contains the synth
* @return the currency key of the supported synth
*/
function getSynthKey(ISwap swap) public view returns (bytes32) {
bytes32 synthKey = swapContracts[address(swap)].synthKey;
require(synthKey != 0x0, "synth key not found for given pool");
return synthKey;
}
/**
* @notice Updates the stored address of the `EXCHANGER` contract. When the Synthetix team upgrades their protocol,
* a new Exchanger contract is deployed. This function manually updates the stored address.
*/
function updateExchangerCache() public {
exchanger = IExchanger(SYNTHETIX_RESOLVER.getAddress(EXCHANGER_NAME));
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "synthetix/contracts/interfaces/ISynthetix.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts-upgradeable/proxy/Initializable.sol";
import "../interfaces/ISwap.sol";
/**
* @title SynthSwapper
* @notice Replacement of Virtual Synths in favor of gas savings. Allows swapping synths via the Synthetix protocol
* or Saddle's pools. The `Bridge.sol` contract will deploy minimal clones of this contract upon initiating
* any cross-asset swaps.
*/
contract SynthSwapper is Initializable {
using SafeERC20 for IERC20;
address payable owner;
// SYNTHETIX points to `ProxyERC20` (0xC011a73ee8576Fb46F5E1c5751cA3B9Fe0af2a6F).
// This contract is a proxy of `Synthetix` and is used to exchange synths.
ISynthetix public constant SYNTHETIX =
ISynthetix(0xC011a73ee8576Fb46F5E1c5751cA3B9Fe0af2a6F);
// "SADDLE" in bytes32 form
bytes32 public constant TRACKING =
0x534144444c450000000000000000000000000000000000000000000000000000;
/**
* @notice Initializes the contract when deploying this directly. This prevents
* others from calling initialize() on the target contract and setting themself as the owner.
*/
constructor() public {
initialize();
}
/**
* @notice This modifier checks if the caller is the owner
*/
modifier onlyOwner() {
require(msg.sender == owner, "is not owner");
_;
}
/**
* @notice Sets the `owner` as the caller of this function
*/
function initialize() public initializer {
require(owner == address(0), "owner already set");
owner = msg.sender;
}
/**
* @notice Swaps the synth to another synth via the Synthetix protocol.
* @param sourceKey currency key of the source synth
* @param synthAmount amount of the synth to swap
* @param destKey currency key of the destination synth
* @return amount of the destination synth received
*/
function swapSynth(
bytes32 sourceKey,
uint256 synthAmount,
bytes32 destKey
) external onlyOwner returns (uint256) {
return
SYNTHETIX.exchangeWithTracking(
sourceKey,
synthAmount,
destKey,
msg.sender,
TRACKING
);
}
/**
* @notice Approves the given `tokenFrom` and swaps it to another token via the given `swap` pool.
* @param swap the address of a pool to swap through
* @param tokenFrom the address of the stored synth
* @param tokenFromIndex the index of the token to swap from
* @param tokenToIndex the token the user wants to swap to
* @param tokenFromAmount the amount of the token to swap
* @param minAmount the min amount the user would like to receive, or revert.
* @param deadline latest timestamp to accept this transaction
* @param recipient the address of the recipient
*/
function swapSynthToToken(
ISwap swap,
IERC20 tokenFrom,
uint8 tokenFromIndex,
uint8 tokenToIndex,
uint256 tokenFromAmount,
uint256 minAmount,
uint256 deadline,
address recipient
) external onlyOwner returns (IERC20, uint256) {
tokenFrom.approve(address(swap), tokenFromAmount);
swap.swap(
tokenFromIndex,
tokenToIndex,
tokenFromAmount,
minAmount,
deadline
);
IERC20 tokenTo = swap.getToken(tokenToIndex);
uint256 balance = tokenTo.balanceOf(address(this));
tokenTo.safeTransfer(recipient, balance);
return (tokenTo, balance);
}
/**
* @notice Withdraws the given amount of `token` to the `recipient`.
* @param token the address of the token to withdraw
* @param recipient the address of the account to receive the token
* @param withdrawAmount the amount of the token to withdraw
* @param shouldDestroy whether this contract should be destroyed after this call
*/
function withdraw(
IERC20 token,
address recipient,
uint256 withdrawAmount,
bool shouldDestroy
) external onlyOwner {
token.safeTransfer(recipient, withdrawAmount);
if (shouldDestroy) {
_destroy();
}
}
/**
* @notice Destroys this contract. Only owner can call this function.
*/
function destroy() external onlyOwner {
_destroy();
}
function _destroy() internal {
selfdestruct(msg.sender);
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
interface IAllowlist {
function getPoolAccountLimit(address poolAddress)
external
view
returns (uint256);
function getPoolCap(address poolAddress) external view returns (uint256);
function verifyAddress(address account, bytes32[] calldata merkleProof)
external
returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity 0.6.12;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "./IAllowlist.sol";
interface ISwap {
// pool data view functions
function getA() external view returns (uint256);
function getAllowlist() external view returns (IAllowlist);
function getToken(uint8 index) external view returns (IERC20);
function getTokenIndex(address tokenAddress) external view returns (uint8);
function getTokenBalance(uint8 index) external view returns (uint256);
function getVirtualPrice() external view returns (uint256);
function isGuarded() external view returns (bool);
// min return calculation functions
function calculateSwap(
uint8 tokenIndexFrom,
uint8 tokenIndexTo,
uint256 dx
) external view returns (uint256);
function calculateTokenAmount(uint256[] calldata amounts, bool deposit)
external
view
returns (uint256);
function calculateRemoveLiquidity(uint256 amount)
external
view
returns (uint256[] memory);
function calculateRemoveLiquidityOneToken(
uint256 tokenAmount,
uint8 tokenIndex
) external view returns (uint256 availableTokenAmount);
// state modifying functions
function initialize(
IERC20[] memory pooledTokens,
uint8[] memory decimals,
string memory lpTokenName,
string memory lpTokenSymbol,
uint256 a,
uint256 fee,
uint256 adminFee,
address lpTokenTargetAddress
) external;
function swap(
uint8 tokenIndexFrom,
uint8 tokenIndexTo,
uint256 dx,
uint256 minDy,
uint256 deadline
) external returns (uint256);
function addLiquidity(
uint256[] calldata amounts,
uint256 minToMint,
uint256 deadline
) external returns (uint256);
function removeLiquidity(
uint256 amount,
uint256[] calldata minAmounts,
uint256 deadline
) external returns (uint256[] memory);
function removeLiquidityOneToken(
uint256 tokenAmount,
uint8 tokenIndex,
uint256 minAmount,
uint256 deadline
) external returns (uint256);
function removeLiquidityImbalance(
uint256[] calldata amounts,
uint256 maxBurnAmount,
uint256 deadline
) external returns (uint256);
}
pragma solidity >=0.4.24;
// https://docs.synthetix.io/contracts/source/interfaces/iaddressresolver
interface IAddressResolver {
function getAddress(bytes32 name) external view returns (address);
function getSynth(bytes32 key) external view returns (address);
function requireAndGetAddress(bytes32 name, string calldata reason) external view returns (address);
}
pragma solidity >=0.4.24;
// https://docs.synthetix.io/contracts/source/interfaces/iexchangerates
interface IExchangeRates {
// Structs
struct RateAndUpdatedTime {
uint216 rate;
uint40 time;
}
struct InversePricing {
uint entryPoint;
uint upperLimit;
uint lowerLimit;
bool frozenAtUpperLimit;
bool frozenAtLowerLimit;
}
// Views
function aggregators(bytes32 currencyKey) external view returns (address);
function aggregatorWarningFlags() external view returns (address);
function anyRateIsInvalid(bytes32[] calldata currencyKeys) external view returns (bool);
function canFreezeRate(bytes32 currencyKey) external view returns (bool);
function currentRoundForRate(bytes32 currencyKey) external view returns (uint);
function currenciesUsingAggregator(address aggregator) external view returns (bytes32[] memory);
function effectiveValue(
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey
) external view returns (uint value);
function effectiveValueAndRates(
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey
)
external
view
returns (
uint value,
uint sourceRate,
uint destinationRate
);
function effectiveValueAtRound(
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey,
uint roundIdForSrc,
uint roundIdForDest
) external view returns (uint value);
function getCurrentRoundId(bytes32 currencyKey) external view returns (uint);
function getLastRoundIdBeforeElapsedSecs(
bytes32 currencyKey,
uint startingRoundId,
uint startingTimestamp,
uint timediff
) external view returns (uint);
function inversePricing(bytes32 currencyKey)
external
view
returns (
uint entryPoint,
uint upperLimit,
uint lowerLimit,
bool frozenAtUpperLimit,
bool frozenAtLowerLimit
);
function lastRateUpdateTimes(bytes32 currencyKey) external view returns (uint256);
function oracle() external view returns (address);
function rateAndTimestampAtRound(bytes32 currencyKey, uint roundId) external view returns (uint rate, uint time);
function rateAndUpdatedTime(bytes32 currencyKey) external view returns (uint rate, uint time);
function rateAndInvalid(bytes32 currencyKey) external view returns (uint rate, bool isInvalid);
function rateForCurrency(bytes32 currencyKey) external view returns (uint);
function rateIsFlagged(bytes32 currencyKey) external view returns (bool);
function rateIsFrozen(bytes32 currencyKey) external view returns (bool);
function rateIsInvalid(bytes32 currencyKey) external view returns (bool);
function rateIsStale(bytes32 currencyKey) external view returns (bool);
function rateStalePeriod() external view returns (uint);
function ratesAndUpdatedTimeForCurrencyLastNRounds(bytes32 currencyKey, uint numRounds)
external
view
returns (uint[] memory rates, uint[] memory times);
function ratesAndInvalidForCurrencies(bytes32[] calldata currencyKeys)
external
view
returns (uint[] memory rates, bool anyRateInvalid);
function ratesForCurrencies(bytes32[] calldata currencyKeys) external view returns (uint[] memory);
// Mutative functions
function freezeRate(bytes32 currencyKey) external;
}
pragma solidity >=0.4.24;
import "./IVirtualSynth.sol";
// https://docs.synthetix.io/contracts/source/interfaces/iexchanger
interface IExchanger {
// Views
function calculateAmountAfterSettlement(
address from,
bytes32 currencyKey,
uint amount,
uint refunded
) external view returns (uint amountAfterSettlement);
function isSynthRateInvalid(bytes32 currencyKey) external view returns (bool);
function maxSecsLeftInWaitingPeriod(address account, bytes32 currencyKey) external view returns (uint);
function settlementOwing(address account, bytes32 currencyKey)
external
view
returns (
uint reclaimAmount,
uint rebateAmount,
uint numEntries
);
function hasWaitingPeriodOrSettlementOwing(address account, bytes32 currencyKey) external view returns (bool);
function feeRateForExchange(bytes32 sourceCurrencyKey, bytes32 destinationCurrencyKey)
external
view
returns (uint exchangeFeeRate);
function getAmountsForExchange(
uint sourceAmount,
bytes32 sourceCurrencyKey,
bytes32 destinationCurrencyKey
)
external
view
returns (
uint amountReceived,
uint fee,
uint exchangeFeeRate
);
function priceDeviationThresholdFactor() external view returns (uint);
function waitingPeriodSecs() external view returns (uint);
// Mutative functions
function exchange(
address from,
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey,
address destinationAddress
) external returns (uint amountReceived);
function exchangeOnBehalf(
address exchangeForAddress,
address from,
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey
) external returns (uint amountReceived);
function exchangeWithTracking(
address from,
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey,
address destinationAddress,
address originator,
bytes32 trackingCode
) external returns (uint amountReceived);
function exchangeOnBehalfWithTracking(
address exchangeForAddress,
address from,
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey,
address originator,
bytes32 trackingCode
) external returns (uint amountReceived);
function exchangeWithVirtual(
address from,
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey,
address destinationAddress,
bytes32 trackingCode
) external returns (uint amountReceived, IVirtualSynth vSynth);
function settle(address from, bytes32 currencyKey)
external
returns (
uint reclaimed,
uint refunded,
uint numEntries
);
function setLastExchangeRateForSynth(bytes32 currencyKey, uint rate) external;
function suspendSynthWithInvalidRate(bytes32 currencyKey) external;
}
pragma solidity >=0.4.24;
// https://docs.synthetix.io/contracts/source/interfaces/isynth
interface ISynth {
// Views
function currencyKey() external view returns (bytes32);
function transferableSynths(address account) external view returns (uint);
// Mutative functions
function transferAndSettle(address to, uint value) external returns (bool);
function transferFromAndSettle(
address from,
address to,
uint value
) external returns (bool);
// Restricted: used internally to Synthetix
function burn(address account, uint amount) external;
function issue(address account, uint amount) external;
}
pragma solidity >=0.4.24;
import "./ISynth.sol";
import "./IVirtualSynth.sol";
// https://docs.synthetix.io/contracts/source/interfaces/isynthetix
interface ISynthetix {
// Views
function anySynthOrSNXRateIsInvalid() external view returns (bool anyRateInvalid);
function availableCurrencyKeys() external view returns (bytes32[] memory);
function availableSynthCount() external view returns (uint);
function availableSynths(uint index) external view returns (ISynth);
function collateral(address account) external view returns (uint);
function collateralisationRatio(address issuer) external view returns (uint);
function debtBalanceOf(address issuer, bytes32 currencyKey) external view returns (uint);
function isWaitingPeriod(bytes32 currencyKey) external view returns (bool);
function maxIssuableSynths(address issuer) external view returns (uint maxIssuable);
function remainingIssuableSynths(address issuer)
external
view
returns (
uint maxIssuable,
uint alreadyIssued,
uint totalSystemDebt
);
function synths(bytes32 currencyKey) external view returns (ISynth);
function synthsByAddress(address synthAddress) external view returns (bytes32);
function totalIssuedSynths(bytes32 currencyKey) external view returns (uint);
function totalIssuedSynthsExcludeEtherCollateral(bytes32 currencyKey) external view returns (uint);
function transferableSynthetix(address account) external view returns (uint transferable);
// Mutative Functions
function burnSynths(uint amount) external;
function burnSynthsOnBehalf(address burnForAddress, uint amount) external;
function burnSynthsToTarget() external;
function burnSynthsToTargetOnBehalf(address burnForAddress) external;
function exchange(
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey
) external returns (uint amountReceived);
function exchangeOnBehalf(
address exchangeForAddress,
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey
) external returns (uint amountReceived);
function exchangeWithTracking(
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey,
address originator,
bytes32 trackingCode
) external returns (uint amountReceived);
function exchangeOnBehalfWithTracking(
address exchangeForAddress,
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey,
address originator,
bytes32 trackingCode
) external returns (uint amountReceived);
function exchangeWithVirtual(
bytes32 sourceCurrencyKey,
uint sourceAmount,
bytes32 destinationCurrencyKey,
bytes32 trackingCode
) external returns (uint amountReceived, IVirtualSynth vSynth);
function issueMaxSynths() external;
function issueMaxSynthsOnBehalf(address issueForAddress) external;
function issueSynths(uint amount) external;
function issueSynthsOnBehalf(address issueForAddress, uint amount) external;
function mint() external returns (bool);
function settle(bytes32 currencyKey)
external
returns (
uint reclaimed,
uint refunded,
uint numEntries
);
// Liquidations
function liquidateDelinquentAccount(address account, uint susdAmount) external returns (bool);
// Restricted Functions
function mintSecondary(address account, uint amount) external;
function mintSecondaryRewards(uint amount) external;
function burnSecondary(address account, uint amount) external;
}
pragma solidity >=0.4.24;
import "./ISynth.sol";
interface IVirtualSynth {
// Views
function balanceOfUnderlying(address account) external view returns (uint);
function rate() external view returns (uint);
function readyToSettle() external view returns (bool);
function secsLeftInWaitingPeriod() external view returns (uint);
function settled() external view returns (bool);
function synth() external view returns (ISynth);
// Mutative functions
function settle(address account) external;
}