Contract Name:
AAveTokenSwap
Contract Source Code:
File 1 of 1 : AAveTokenSwap
// File: openzeppelin-solidity/contracts/token/ERC20/IERC20.sol
pragma solidity ^0.5.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP. Does not include
* the optional functions; to access them see {ERC20Detailed}.
*/
interface IERC20 {
/**
* @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);
}
// File: openzeppelin-solidity/contracts/math/SafeMath.sol
pragma solidity ^0.5.0;
/**
* @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, 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) {
return sub(a, b, "SafeMath: subtraction overflow");
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
* - Subtraction cannot overflow.
*
* _Available since v2.4.0._
*/
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
/**
* @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) {
// 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 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts 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) {
return div(a, b, "SafeMath: division by zero");
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts with custom message on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*
* _Available since v2.4.0._
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0, errorMessage);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, "SafeMath: modulo by zero");
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts with custom message 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.
*
* _Available since v2.4.0._
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
// File: openzeppelin-solidity/contracts/utils/Address.sol
pragma solidity ^0.5.5;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* This test is non-exhaustive, and there may be false-negatives: during the
* execution of a contract's constructor, its address will be reported as
* not containing 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.
*/
function isContract(address account) internal view returns (bool) {
// This method relies in extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
// According to EIP-1052, 0x0 is the value returned for not-yet created accounts
// and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
// for accounts without code, i.e. `keccak256('')`
bytes32 codehash;
bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
// solhint-disable-next-line no-inline-assembly
assembly { codehash := extcodehash(account) }
return (codehash != 0x0 && codehash != accountHash);
}
/**
* @dev Converts an `address` into `address payable`. Note that this is
* simply a type cast: the actual underlying value is not changed.
*
* _Available since v2.4.0._
*/
function toPayable(address account) internal pure returns (address payable) {
return address(uint160(account));
}
/**
* @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].
*
* _Available since v2.4.0._
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-call-value
(bool success, ) = recipient.call.value(amount)("");
require(success, "Address: unable to send value, recipient may have reverted");
}
}
// File: openzeppelin-solidity/contracts/token/ERC20/SafeERC20.sol
pragma solidity ^0.5.0;
/**
* @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 ERC20;` 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));
}
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.
// A Solidity high level call has three parts:
// 1. The target address is checked to verify it contains contract code
// 2. The call itself is made, and success asserted
// 3. The return value is decoded, which in turn checks the size of the returned data.
// solhint-disable-next-line max-line-length
require(address(token).isContract(), "SafeERC20: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = address(token).call(data);
require(success, "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");
}
}
}
// File: contracts/Interfaces/AAve.sol
pragma solidity ^0.5.0;
interface AAve_LendingPoolAddressesProvider {
function getLendingPool() external view returns (address);
function getLendingPoolCore() external view returns (address payable);
}
interface AAve_LendingPool {
function deposit(address _reserve, uint256 _amount, uint16 _referralCode) external payable;
}
interface AAve_LendingPoolCore {
function getReserveATokenAddress(address _reserve) external view returns (address);
}
interface AAve_aToken {
function underlyingAssetAddress() external returns(address);
function redeem(uint256 _amount) external;
// ERC20 methods
function balanceOf(address account) external view returns (uint256);
function allowance(address owner, address spender) external view returns (uint256);
function approve(address spender, uint256 value) external returns (bool);
}
// File: contracts/Interfaces/IBadStaticCallERC20.sol
pragma solidity ^0.5.0;
/**
* @dev Interface to be safe with not so good proxy contracts.
*/
interface IBadStaticCallERC20 {
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external returns (uint256);
/**
* @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 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);
}
// File: openzeppelin-solidity/contracts/GSN/Context.sol
pragma solidity ^0.5.0;
/*
* @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.
*/
contract Context {
// Empty internal constructor, to prevent people from mistakenly deploying
// an instance of this contract, which should be used via inheritance.
constructor () internal { }
// solhint-disable-previous-line no-empty-blocks
function _msgSender() internal view returns (address payable) {
return msg.sender;
}
function _msgData() internal view returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// File: openzeppelin-solidity/contracts/Ownership/Ownable.sol
pragma solidity ^0.5.0;
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor () internal {
_owner = _msgSender();
emit OwnershipTransferred(address(0), _owner);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(isOwner(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Returns true if the caller is the current owner.
*/
function isOwner() public view returns (bool) {
return _msgSender() == _owner;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public onlyOwner {
_transferOwnership(newOwner);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
*/
function _transferOwnership(address newOwner) internal {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
// File: contracts/Utils/Destructible.sol
pragma solidity >=0.5.0;
/**
* @title Destructible
* @dev Base contract that can be destroyed by owner. All funds in contract will be sent to the owner.
*/
contract Destructible is Ownable {
/**
* @dev Transfers the current balance to the owner and terminates the contract.
*/
function destroy() public onlyOwner {
selfdestruct(address(bytes20(owner())));
}
function destroyAndSend(address payable _recipient) public onlyOwner {
selfdestruct(_recipient);
}
}
// File: contracts/Utils/Pausable.sol
pragma solidity >=0.4.24;
/**
* @title Pausable
* @dev Base contract which allows children to implement an emergency stop mechanism.
*/
contract Pausable is Ownable {
event Pause();
event Unpause();
bool public paused = false;
/**
* @dev Modifier to make a function callable only when the contract is not paused.
*/
modifier whenNotPaused() {
require(!paused, "The contract is paused");
_;
}
/**
* @dev Modifier to make a function callable only when the contract is paused.
*/
modifier whenPaused() {
require(paused, "The contract is not paused");
_;
}
/**
* @dev called by the owner to pause, triggers stopped state
*/
function pause() public onlyOwner whenNotPaused {
paused = true;
emit Pause();
}
/**
* @dev called by the owner to unpause, returns to normal state
*/
function unpause() public onlyOwner whenPaused {
paused = false;
emit Unpause();
}
}
// File: openzeppelin-solidity/contracts/token/ERC20/ERC20.sol
pragma solidity ^0.5.0;
/**
* @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 {ERC20Mintable}.
*
* 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;
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view 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 returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public 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 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 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 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 {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_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 {
require(account != address(0), "ERC20: mint to the zero address");
_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 {
require(account != address(0), "ERC20: burn from the zero address");
_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 is 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 {
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 Destroys `amount` tokens from `account`.`amount` is then deducted
* from the caller's allowance.
*
* See {_burn} and {_approve}.
*/
function _burnFrom(address account, uint256 amount) internal {
_burn(account, amount);
_approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "ERC20: burn amount exceeds allowance"));
}
}
// File: contracts/Utils/Withdrawable.sol
pragma solidity >=0.4.24;
contract Withdrawable is Ownable {
using SafeERC20 for ERC20;
address constant ETHER = address(0);
event LogWithdrawToken(
address indexed _from,
address indexed _token,
uint amount
);
/**
* @dev Withdraw asset.
* @param _tokenAddress Asset to be withdrawed.
* @return bool.
*/
function withdrawToken(address _tokenAddress) public onlyOwner {
uint tokenBalance;
if (_tokenAddress == ETHER) {
address self = address(this); // workaround for a possible solidity bug
tokenBalance = self.balance;
msg.sender.transfer(tokenBalance);
} else {
tokenBalance = ERC20(_tokenAddress).balanceOf(address(this));
ERC20(_tokenAddress).safeTransfer(msg.sender, tokenBalance);
}
emit LogWithdrawToken(msg.sender, _tokenAddress, tokenBalance);
}
}
// File: contracts/Utils/WithFee.sol
pragma solidity ^0.5.0;
contract WithFee is Ownable {
using SafeERC20 for IERC20;
using SafeMath for uint;
address payable public feeWallet;
uint public storedSpread;
uint constant spreadDecimals = 6;
uint constant spreadUnit = 10 ** spreadDecimals;
event LogFee(address token, uint amount);
constructor(address payable _wallet, uint _spread) public {
require(_wallet != address(0), "_wallet == address(0)");
require(_spread < spreadUnit, "spread >= spreadUnit");
feeWallet = _wallet;
storedSpread = _spread;
}
function setFeeWallet(address payable _wallet) external onlyOwner {
require(_wallet != address(0), "_wallet == address(0)");
feeWallet = _wallet;
}
function setSpread(uint _spread) external onlyOwner {
storedSpread = _spread;
}
function _getFee(uint underlyingTokenTotal) internal view returns(uint) {
return underlyingTokenTotal.mul(storedSpread).div(spreadUnit);
}
function _payFee(address feeToken, uint fee) internal {
if (fee > 0) {
if (feeToken == address(0)) {
feeWallet.transfer(fee);
} else {
IERC20(feeToken).safeTransfer(feeWallet, fee);
}
emit LogFee(feeToken, fee);
}
}
}
// File: contracts/Interfaces/IErc20Swap.sol
pragma solidity >=0.4.0;
interface IErc20Swap {
function getRate(address src, address dst, uint256 srcAmount) external view returns(uint expectedRate, uint slippageRate); // real rate = returned value / 1e18
function swap(address src, uint srcAmount, address dest, uint maxDestAmount, uint minConversionRate) external payable;
event LogTokenSwap(
address indexed _userAddress,
address indexed _userSentTokenAddress,
uint _userSentTokenAmount,
address indexed _userReceivedTokenAddress,
uint _userReceivedTokenAmount
);
}
// File: contracts/base/NetworkBasedTokenSwap.sol
pragma solidity >=0.5.0;
contract NetworkBasedTokenSwap is Withdrawable, Pausable, Destructible, WithFee, IErc20Swap
{
using SafeMath for uint;
using SafeERC20 for IERC20;
address constant ETHER = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
mapping (address => mapping (address => uint)) spreadCustom;
event UnexpectedIntialBalance(address token, uint amount);
constructor(
address payable _wallet,
uint _spread
)
public WithFee(_wallet, _spread)
{}
function() external payable {
// can receive ethers
}
// spread value >= spreadUnit means no fee
function setSpread(address tokenA, address tokenB, uint spread) public onlyOwner {
uint value = spread > spreadUnit ? spreadUnit : spread;
spreadCustom[tokenA][tokenB] = value;
spreadCustom[tokenB][tokenA] = value;
}
function getSpread(address tokenA, address tokenB) public view returns(uint) {
uint value = spreadCustom[tokenA][tokenB];
if (value == 0) return storedSpread;
if (value >= spreadUnit) return 0;
else return value;
}
// kyber network style rate
function getNetworkRate(address src, address dest, uint256 srcAmount) internal view returns(uint expectedRate, uint slippageRate);
function getRate(address src, address dest, uint256 srcAmount) external view
returns(uint expectedRate, uint slippageRate)
{
(uint256 kExpected, uint256 kSplippage) = getNetworkRate(src, dest, srcAmount);
uint256 spread = getSpread(src, dest);
expectedRate = kExpected.mul(spreadUnit - spread).div(spreadUnit);
slippageRate = kSplippage.mul(spreadUnit - spread).div(spreadUnit);
}
function _freeUnexpectedTokens(address token) private {
uint256 unexpectedBalance = token == ETHER
? _myEthBalance().sub(msg.value)
: IBadStaticCallERC20(token).balanceOf(address(this));
if (unexpectedBalance > 0) {
_transfer(token, address(bytes20(owner())), unexpectedBalance);
emit UnexpectedIntialBalance(token, unexpectedBalance);
}
}
function swap(address src, uint srcAmount, address dest, uint maxDestAmount, uint minConversionRate) public payable {
require(src != dest, "src == dest");
require(srcAmount > 0, "srcAmount == 0");
// empty unexpected initial balances
_freeUnexpectedTokens(src);
_freeUnexpectedTokens(dest);
if (src == ETHER) {
require(msg.value == srcAmount, "msg.value != srcAmount");
} else {
require(
IBadStaticCallERC20(src).allowance(msg.sender, address(this)) >= srcAmount,
"ERC20 allowance < srcAmount"
);
// get user's tokens
IERC20(src).safeTransferFrom(msg.sender, address(this), srcAmount);
}
uint256 spread = getSpread(src, dest);
// calculate the minConversionRate and maxDestAmount keeping in mind the fee
uint256 adaptedMinRate = minConversionRate.mul(spreadUnit).div(spreadUnit - spread);
uint256 adaptedMaxDestAmount = maxDestAmount.mul(spreadUnit).div(spreadUnit - spread);
uint256 destTradedAmount = doNetworkTrade(src, srcAmount, dest, adaptedMaxDestAmount, adaptedMinRate);
uint256 notTraded = _myBalance(src);
uint256 srcTradedAmount = srcAmount.sub(notTraded);
require(srcTradedAmount > 0, "no traded tokens");
require(
_myBalance(dest) >= destTradedAmount,
"No enough dest tokens after trade"
);
// pay fee and user
uint256 toUserAmount = _payFee(dest, destTradedAmount, spread);
_transfer(dest, msg.sender, toUserAmount);
// returns not traded tokens if any
if (notTraded > 0) {
_transfer(src, msg.sender, notTraded);
}
emit LogTokenSwap(
msg.sender,
src,
srcTradedAmount,
dest,
toUserAmount
);
}
function doNetworkTrade(address src, uint srcAmount, address dest, uint maxDestAmount, uint minConversionRate) internal returns(uint256);
function _payFee(address token, uint destTradedAmount, uint spread) private returns(uint256 toUserAmount) {
uint256 fee = destTradedAmount.mul(spread).div(spreadUnit);
toUserAmount = destTradedAmount.sub(fee);
// pay fee
super._payFee(token == ETHER ? address(0) : token, fee);
}
// workaround for a solidity bug
function _myEthBalance() private view returns(uint256) {
address self = address(this);
return self.balance;
}
function _myBalance(address token) private returns(uint256) {
return token == ETHER
? _myEthBalance()
: IBadStaticCallERC20(token).balanceOf(address(this));
}
function _transfer(address token, address payable recipient, uint256 amount) private {
if (token == ETHER) {
recipient.transfer(amount);
} else {
IERC20(token).safeTransfer(recipient, amount);
}
}
}
// File: contracts/Utils/SafeStaticCallERC20.sol
pragma solidity ^0.5.0;
library SafeStaticCallERC20 {
using SafeMath for uint256;
using Address for address;
function safeApprove(IBadStaticCallERC20 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),
"SafeProxyERC20: approve from non-zero to non-zero allowance"
);
callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
/**
* @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(IBadStaticCallERC20 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.
// A Solidity high level call has three parts:
// 1. The target address is checked to verify it contains contract code
// 2. The call itself is made, and success asserted
// 3. The return value is decoded, which in turn checks the size of the returned data.
// solhint-disable-next-line max-line-length
require(address(token).isContract(), "SafeProxyERC20: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = address(token).call(data);
require(success, "SafeProxyERC20: low-level call failed");
if (returndata.length > 0) { // Return data is optional
// solhint-disable-next-line max-line-length
require(abi.decode(returndata, (bool)), "SafeProxyERC20: ERC20 operation did not succeed");
}
}
}
// File: contracts/Utils/LowLevel.sol
pragma solidity ^0.5.0;
library LowLevel {
function staticCallContractAddr(address target, bytes memory payload) internal view
returns (bool success_, address result_)
{
(bool success, bytes memory result) = address(target).staticcall(payload);
if (success && result.length == 32) {
return (true, abi.decode(result, (address)));
}
return (false, address(0));
}
function callContractAddr(address target, bytes memory payload) internal
returns (bool success_, address result_)
{
(bool success, bytes memory result) = address(target).call(payload);
if (success && result.length == 32) {
return (true, abi.decode(result, (address)));
}
return (false, address(0));
}
function staticCallContractUint(address target, bytes memory payload) internal view
returns (bool success_, uint result_)
{
(bool success, bytes memory result) = address(target).staticcall(payload);
if (success && result.length == 32) {
return (true, abi.decode(result, (uint)));
}
return (false, 0);
}
function callContractUint(address target, bytes memory payload) internal
returns (bool success_, uint result_)
{
(bool success, bytes memory result) = address(target).call(payload);
if (success && result.length == 32) {
return (true, abi.decode(result, (uint)));
}
return (false, 0);
}
}
// File: contracts/AAveTokenSwap.sol
pragma solidity >=0.5.0;
contract AAveTokenSwap is NetworkBasedTokenSwap
{
using SafeMath for uint;
using SafeERC20 for IERC20;
using SafeStaticCallERC20 for IBadStaticCallERC20;
address constant AAVE_ETHER = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
uint constant rateUnit = 10 ** 18;
AAve_LendingPoolAddressesProvider public addressesProvider;
uint16 public aaveReferralCode;
constructor(
address _aaveAddressProvider,
address payable _wallet,
uint16 _aaveReferralCode,
uint _spread
)
public NetworkBasedTokenSwap(_wallet, _spread)
{
require(_aaveAddressProvider != address(0), "_aaveAddressProvider == address(0)");
addressesProvider = AAve_LendingPoolAddressesProvider(_aaveAddressProvider);
aaveReferralCode = _aaveReferralCode;
}
function setAAveReferralCode(uint16 _code) public onlyOwner {
aaveReferralCode = _code;
}
function getNetworkRate(address src, address dest, uint256 /*srcAmount*/) internal view
returns(uint expectedRate, uint slippageRate)
{
AAve_LendingPoolCore core = AAve_LendingPoolCore(addressesProvider.getLendingPoolCore());
address aethAddr = core.getReserveATokenAddress(AAVE_ETHER);
if ((src == ETHER && dest != aethAddr) ||
(dest == ETHER && src != aethAddr))
{
return (0, 0);
} else {
//return (rateUnit, rateUnit); // FIXME: should return (0,0) if the pair is not valid
}
return (rateUnit, rateUnit);
}
function isWrap(address src, address dest) internal returns(bool) {
bytes memory payloadUnwrap = abi.encodeWithSignature("underlyingAssetAddress()");
(bool success, address effectiveDest) = LowLevel.callContractAddr(src, payloadUnwrap);
if (success && effectiveDest != address(0)) {
require(dest == effectiveDest, "Invalid pair");
return false;
} else {
bytes memory payloadWrap = abi.encodeWithSignature("getReserveATokenAddress(address)", src);
address core = addressesProvider.getLendingPoolCore();
(success, effectiveDest) = LowLevel.callContractAddr(core, payloadWrap);
require(success && dest == effectiveDest, "Invalid pair");
return true;
}
}
function doNetworkTrade(address src, uint srcAmount, address dest, uint /*maxDestAmount*/, uint /*minConversionRate*/)
internal returns(uint256)
{
AAve_LendingPool lendingPool = AAve_LendingPool(addressesProvider.getLendingPool());
if (src == ETHER) {
AAve_LendingPoolCore core = AAve_LendingPoolCore(addressesProvider.getLendingPoolCore());
address aEthAddr = core.getReserveATokenAddress(AAVE_ETHER);
require(dest == aEthAddr, "dest != aETH address");
lendingPool.deposit.value(srcAmount)(AAVE_ETHER, srcAmount, aaveReferralCode);
return IERC20(aEthAddr).balanceOf(address(this));
} else if (dest == ETHER) {
AAve_LendingPoolCore core = AAve_LendingPoolCore(addressesProvider.getLendingPoolCore());
address aEthAddr = core.getReserveATokenAddress(AAVE_ETHER);
require(src == aEthAddr, "src != aETH address");
AAve_aToken(aEthAddr).redeem(srcAmount);
return address(this).balance;
} else {
address core = addressesProvider.getLendingPoolCore();
if (isWrap(src, dest)) {
if (IBadStaticCallERC20(src).allowance(address(this), core) > 0) {
IBadStaticCallERC20(src).safeApprove(core, 0);
}
IBadStaticCallERC20(src).safeApprove(core, srcAmount);
lendingPool.deposit(src, srcAmount, aaveReferralCode);
} else {
AAve_aToken(src).redeem(srcAmount);
}
return IBadStaticCallERC20(dest).balanceOf(address(this));
}
}
}