Contract Name:
RewardsDistributor
Contract Source Code:
File 1 of 1 : RewardsDistributor
pragma solidity 0.5.16;
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);
}
interface IRewardsDistributionRecipient {
function notifyRewardAmount(uint256 reward) external;
function getRewardToken() external view returns (IERC20);
}
contract InitializableModuleKeys {
// Governance // Phases
bytes32 internal KEY_GOVERNANCE; // 2.x
bytes32 internal KEY_STAKING; // 1.2
bytes32 internal KEY_PROXY_ADMIN; // 1.0
// mStable
bytes32 internal KEY_ORACLE_HUB; // 1.2
bytes32 internal KEY_MANAGER; // 1.2
bytes32 internal KEY_RECOLLATERALISER; // 2.x
bytes32 internal KEY_META_TOKEN; // 1.1
bytes32 internal KEY_SAVINGS_MANAGER; // 1.0
/**
* @dev Initialize function for upgradable proxy contracts. This function should be called
* via Proxy to initialize constants in the Proxy contract.
*/
function _initialize() internal {
// keccak256() values are evaluated only once at the time of this function call.
// Hence, no need to assign hard-coded values to these variables.
KEY_GOVERNANCE = keccak256("Governance");
KEY_STAKING = keccak256("Staking");
KEY_PROXY_ADMIN = keccak256("ProxyAdmin");
KEY_ORACLE_HUB = keccak256("OracleHub");
KEY_MANAGER = keccak256("Manager");
KEY_RECOLLATERALISER = keccak256("Recollateraliser");
KEY_META_TOKEN = keccak256("MetaToken");
KEY_SAVINGS_MANAGER = keccak256("SavingsManager");
}
}
interface INexus {
function governor() external view returns (address);
function getModule(bytes32 key) external view returns (address);
function proposeModule(bytes32 _key, address _addr) external;
function cancelProposedModule(bytes32 _key) external;
function acceptProposedModule(bytes32 _key) external;
function acceptProposedModules(bytes32[] calldata _keys) external;
function requestLockModule(bytes32 _key) external;
function cancelLockModule(bytes32 _key) external;
function lockModule(bytes32 _key) external;
}
contract InitializableModule is InitializableModuleKeys {
INexus public nexus;
/**
* @dev Modifier to allow function calls only from the Governor.
*/
modifier onlyGovernor() {
require(msg.sender == _governor(), "Only governor can execute");
_;
}
/**
* @dev Modifier to allow function calls only from the Governance.
* Governance is either Governor address or Governance address.
*/
modifier onlyGovernance() {
require(
msg.sender == _governor() || msg.sender == _governance(),
"Only governance can execute"
);
_;
}
/**
* @dev Modifier to allow function calls only from the ProxyAdmin.
*/
modifier onlyProxyAdmin() {
require(
msg.sender == _proxyAdmin(), "Only ProxyAdmin can execute"
);
_;
}
/**
* @dev Modifier to allow function calls only from the Manager.
*/
modifier onlyManager() {
require(msg.sender == _manager(), "Only manager can execute");
_;
}
/**
* @dev Initialization function for upgradable proxy contracts
* @param _nexus Nexus contract address
*/
function _initialize(address _nexus) internal {
require(_nexus != address(0), "Nexus address is zero");
nexus = INexus(_nexus);
InitializableModuleKeys._initialize();
}
/**
* @dev Returns Governor address from the Nexus
* @return Address of Governor Contract
*/
function _governor() internal view returns (address) {
return nexus.governor();
}
/**
* @dev Returns Governance Module address from the Nexus
* @return Address of the Governance (Phase 2)
*/
function _governance() internal view returns (address) {
return nexus.getModule(KEY_GOVERNANCE);
}
/**
* @dev Return Staking Module address from the Nexus
* @return Address of the Staking Module contract
*/
function _staking() internal view returns (address) {
return nexus.getModule(KEY_STAKING);
}
/**
* @dev Return ProxyAdmin Module address from the Nexus
* @return Address of the ProxyAdmin Module contract
*/
function _proxyAdmin() internal view returns (address) {
return nexus.getModule(KEY_PROXY_ADMIN);
}
/**
* @dev Return MetaToken Module address from the Nexus
* @return Address of the MetaToken Module contract
*/
function _metaToken() internal view returns (address) {
return nexus.getModule(KEY_META_TOKEN);
}
/**
* @dev Return OracleHub Module address from the Nexus
* @return Address of the OracleHub Module contract
*/
function _oracleHub() internal view returns (address) {
return nexus.getModule(KEY_ORACLE_HUB);
}
/**
* @dev Return Manager Module address from the Nexus
* @return Address of the Manager Module contract
*/
function _manager() internal view returns (address) {
return nexus.getModule(KEY_MANAGER);
}
/**
* @dev Return SavingsManager Module address from the Nexus
* @return Address of the SavingsManager Module contract
*/
function _savingsManager() internal view returns (address) {
return nexus.getModule(KEY_SAVINGS_MANAGER);
}
/**
* @dev Return Recollateraliser Module address from the Nexus
* @return Address of the Recollateraliser Module contract (Phase 2)
*/
function _recollateraliser() internal view returns (address) {
return nexus.getModule(KEY_RECOLLATERALISER);
}
}
contract InitializableGovernableWhitelist is InitializableModule {
event Whitelisted(address indexed _address);
mapping(address => bool) public whitelist;
/**
* @dev Modifier to allow function calls only from the whitelisted address.
*/
modifier onlyWhitelisted() {
require(whitelist[msg.sender], "Not a whitelisted address");
_;
}
/**
* @dev Initialization function for upgradable proxy contracts
* @param _nexus Nexus contract address
* @param _whitelisted Array of whitelisted addresses.
*/
function _initialize(
address _nexus,
address[] memory _whitelisted
)
internal
{
InitializableModule._initialize(_nexus);
require(_whitelisted.length > 0, "Empty whitelist array");
for(uint256 i = 0; i < _whitelisted.length; i++) {
_addWhitelist(_whitelisted[i]);
}
}
/**
* @dev Adds a new whitelist address
* @param _address Address to add in whitelist
*/
function _addWhitelist(address _address) internal {
require(_address != address(0), "Address is zero");
require(! whitelist[_address], "Already whitelisted");
whitelist[_address] = true;
emit Whitelisted(_address);
}
}
/**
* @dev Interface of the ERC20 standard as defined in the EIP. Does not include
* the optional functions; to access them see {ERC20Detailed}.
*/
/**
* @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;
}
}
/**
* @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) {
// 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 != accountHash && codehash != 0x0);
}
/**
* @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");
}
}
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");
}
}
}
/**
* @title RewardsDistributor
* @author Stability Labs Pty. Ltd.
* @notice RewardsDistributor allows Fund Managers to send rewards (usually in MTA)
* to specified Reward Recipients.
*/
contract RewardsDistributor is InitializableGovernableWhitelist {
using SafeERC20 for IERC20;
event RemovedFundManager(address indexed _address);
event DistributedReward(address funder, address recipient, address rewardToken, uint256 amount);
/** @dev Recipient is a module, governed by mStable governance */
constructor(
address _nexus,
address[] memory _fundManagers
)
public
{
InitializableGovernableWhitelist._initialize(_nexus, _fundManagers);
}
/**
* @dev Allows the mStable governance to add a new FundManager
* @param _address FundManager to add
*/
function addFundManager(address _address)
external
onlyGovernor
{
_addWhitelist(_address);
}
/**
* @dev Allows the mStable governance to remove inactive FundManagers
* @param _address FundManager to remove
*/
function removeFundManager(address _address)
external
onlyGovernor
{
require(_address != address(0), "Address is zero");
require(whitelist[_address], "Address is not whitelisted");
whitelist[_address] = false;
emit RemovedFundManager(_address);
}
/**
* @dev Distributes reward tokens to list of recipients and notifies them
* of the transfer. Only callable by FundManagers
* @param _recipients Array of Reward recipients to credit
* @param _amounts Amounts of reward tokens to distribute
*/
function distributeRewards(
IRewardsDistributionRecipient[] calldata _recipients,
uint256[] calldata _amounts
)
external
onlyWhitelisted
{
uint256 len = _recipients.length;
require(len > 0, "Must choose recipients");
require(len == _amounts.length, "Mismatching inputs");
for(uint i = 0; i < len; i++){
uint256 amount = _amounts[i];
IRewardsDistributionRecipient recipient = _recipients[i];
// Send the RewardToken to recipient
IERC20 rewardToken = recipient.getRewardToken();
rewardToken.safeTransferFrom(msg.sender, address(recipient), amount);
// Only after successfull tx - notify the contract of the new funds
recipient.notifyRewardAmount(amount);
emit DistributedReward(msg.sender, address(recipient), address(rewardToken), amount);
}
}
}