Contract Name:
RewardTracker
Contract Source Code:
File 1 of 1 : RewardTracker
pragma solidity 0.6.12;
/**
* @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.
*/
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.
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
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.
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
/**
* @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);
}
/**
* @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 v3.3._
*/
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 v3.3._
*/
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);
}
}
}
}
/**
* @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");
}
}
}
/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*
* TIP: If you would like to learn more about reentrancy and alternative ways
* to protect against it, check out our blog post
* https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
*/
contract ReentrancyGuard {
// Booleans are more expensive than uint256 or any type that takes up a full
// word because each write operation emits an extra SLOAD to first read the
// slot's contents, replace the bits taken up by the boolean, and then write
// back. This is the compiler's defense against contract upgrades and
// pointer aliasing, and it cannot be disabled.
// The values being non-zero value makes deployment a bit more expensive,
// but in exchange the refund on every call to nonReentrant will be lower in
// amount. Since refunds are capped to a percentage of the total
// transaction's gas, it is best to keep them low in cases like this one, to
// increase the likelihood of the full refund coming into effect.
uint256 private constant _NOT_ENTERED = 1;
uint256 private constant _ENTERED = 2;
uint256 private _status;
constructor () internal {
_status = _NOT_ENTERED;
}
/**
* @dev Prevents a contract from calling itself, directly or indirectly.
* Calling a `nonReentrant` function from another `nonReentrant`
* function is not supported. It is possible to prevent this from happening
* by making the `nonReentrant` function external, and make it call a
* `private` function that does the actual work.
*/
modifier nonReentrant() {
// On the first call to nonReentrant, _notEntered will be true
require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
_;
// By storing the original value once again, a refund is triggered (see
// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
}
interface IRewardDistributor {
function rewardToken() external view returns (address);
function tokensPerInterval() external view returns (uint256);
function pendingRewards() external view returns (uint256);
function distribute() external returns (uint256);
}
interface IRewardTracker {
function depositBalances(address _account, address _depositToken) external view returns (uint256);
function stakedAmounts(address _account) external view returns (uint256);
function updateRewards() external;
function stake(address _depositToken, uint256 _amount) external;
function stakeForAccount(address _fundingAccount, address _account, address _depositToken, uint256 _amount) external;
function unstake(address _depositToken, uint256 _amount) external;
function unstakeForAccount(address _account, address _depositToken, uint256 _amount, address _receiver) external;
function tokensPerInterval() external view returns (uint256);
function claim(address _receiver) external returns (uint256);
function claimForAccount(address _account, address _receiver) external returns (uint256);
function claimable(address _account) external view returns (uint256);
function averageStakedAmounts(address _account) external view returns (uint256);
function cumulativeRewards(address _account) external view returns (uint256);
}
contract Governable {
address public gov;
constructor() public {
gov = msg.sender;
}
modifier onlyGov() {
require(msg.sender == gov, "Governable: forbidden");
_;
}
function setGov(address _gov) external onlyGov {
gov = _gov;
}
}
contract RewardTracker is IERC20, ReentrancyGuard, IRewardTracker, Governable {
using SafeMath for uint256;
using SafeERC20 for IERC20;
uint256 public constant BASIS_POINTS_DIVISOR = 10000;
uint256 public constant PRECISION = 1e30;
uint8 public constant decimals = 18;
bool public isInitialized;
string public name;
string public symbol;
address public distributor;
mapping (address => bool) public isDepositToken;
mapping (address => mapping (address => uint256)) public override depositBalances;
mapping (address => uint256) public totalDepositSupply;
uint256 public override totalSupply;
mapping (address => uint256) public balances;
mapping (address => mapping (address => uint256)) public allowances;
uint256 public cumulativeRewardPerToken;
mapping (address => uint256) public override stakedAmounts;
mapping (address => uint256) public claimableReward;
mapping (address => uint256) public previousCumulatedRewardPerToken;
mapping (address => uint256) public override cumulativeRewards;
mapping (address => uint256) public override averageStakedAmounts;
bool public inPrivateTransferMode;
bool public inPrivateStakingMode;
bool public inPrivateClaimingMode;
mapping (address => bool) public isHandler;
event Claim(address receiver, uint256 amount);
constructor(string memory _name, string memory _symbol) public {
name = _name;
symbol = _symbol;
}
function initialize(
address[] memory _depositTokens,
address _distributor
) external onlyGov {
require(!isInitialized, "RewardTracker: already initialized");
isInitialized = true;
for (uint256 i = 0; i < _depositTokens.length; i++) {
address depositToken = _depositTokens[i];
isDepositToken[depositToken] = true;
}
distributor = _distributor;
}
function setDepositToken(address _depositToken, bool _isDepositToken) external onlyGov {
isDepositToken[_depositToken] = _isDepositToken;
}
function setInPrivateTransferMode(bool _inPrivateTransferMode) external onlyGov {
inPrivateTransferMode = _inPrivateTransferMode;
}
function setInPrivateStakingMode(bool _inPrivateStakingMode) external onlyGov {
inPrivateStakingMode = _inPrivateStakingMode;
}
function setInPrivateClaimingMode(bool _inPrivateClaimingMode) external onlyGov {
inPrivateClaimingMode = _inPrivateClaimingMode;
}
function setHandler(address _handler, bool _isActive) external onlyGov {
isHandler[_handler] = _isActive;
}
// to help users who accidentally send their tokens to this contract
function withdrawToken(address _token, address _account, uint256 _amount) external onlyGov {
IERC20(_token).safeTransfer(_account, _amount);
}
function balanceOf(address _account) external view override returns (uint256) {
return balances[_account];
}
function stake(address _depositToken, uint256 _amount) external override nonReentrant {
if (inPrivateStakingMode) { revert("RewardTracker: action not enabled"); }
_stake(msg.sender, msg.sender, _depositToken, _amount);
}
function stakeForAccount(address _fundingAccount, address _account, address _depositToken, uint256 _amount) external override nonReentrant {
_validateHandler();
_stake(_fundingAccount, _account, _depositToken, _amount);
}
function unstake(address _depositToken, uint256 _amount) external override nonReentrant {
if (inPrivateStakingMode) { revert("RewardTracker: action not enabled"); }
_unstake(msg.sender, _depositToken, _amount, msg.sender);
}
function unstakeForAccount(address _account, address _depositToken, uint256 _amount, address _receiver) external override nonReentrant {
_validateHandler();
_unstake(_account, _depositToken, _amount, _receiver);
}
function transfer(address _recipient, uint256 _amount) external override returns (bool) {
_transfer(msg.sender, _recipient, _amount);
return true;
}
function allowance(address _owner, address _spender) external view override returns (uint256) {
return allowances[_owner][_spender];
}
function approve(address _spender, uint256 _amount) external override returns (bool) {
_approve(msg.sender, _spender, _amount);
return true;
}
function transferFrom(address _sender, address _recipient, uint256 _amount) external override returns (bool) {
if (isHandler[msg.sender]) {
_transfer(_sender, _recipient, _amount);
return true;
}
uint256 nextAllowance = allowances[_sender][msg.sender].sub(_amount, "RewardTracker: transfer amount exceeds allowance");
_approve(_sender, msg.sender, nextAllowance);
_transfer(_sender, _recipient, _amount);
return true;
}
function tokensPerInterval() external override view returns (uint256) {
return IRewardDistributor(distributor).tokensPerInterval();
}
function updateRewards() external override nonReentrant {
_updateRewards(address(0));
}
function claim(address _receiver) external override nonReentrant returns (uint256) {
if (inPrivateClaimingMode) { revert("RewardTracker: action not enabled"); }
return _claim(msg.sender, _receiver);
}
function claimForAccount(address _account, address _receiver) external override nonReentrant returns (uint256) {
_validateHandler();
return _claim(_account, _receiver);
}
function claimable(address _account) public override view returns (uint256) {
uint256 stakedAmount = stakedAmounts[_account];
if (stakedAmount == 0) {
return claimableReward[_account];
}
uint256 supply = totalSupply;
uint256 pendingRewards = IRewardDistributor(distributor).pendingRewards().mul(PRECISION);
uint256 nextCumulativeRewardPerToken = cumulativeRewardPerToken.add(pendingRewards.div(supply));
return claimableReward[_account].add(
stakedAmount.mul(nextCumulativeRewardPerToken.sub(previousCumulatedRewardPerToken[_account])).div(PRECISION));
}
function rewardToken() public view returns (address) {
return IRewardDistributor(distributor).rewardToken();
}
function _claim(address _account, address _receiver) private returns (uint256) {
_updateRewards(_account);
uint256 tokenAmount = claimableReward[_account];
claimableReward[_account] = 0;
if (tokenAmount > 0) {
IERC20(rewardToken()).safeTransfer(_receiver, tokenAmount);
emit Claim(_account, tokenAmount);
}
return tokenAmount;
}
function _mint(address _account, uint256 _amount) internal {
require(_account != address(0), "RewardTracker: mint to the zero address");
totalSupply = totalSupply.add(_amount);
balances[_account] = balances[_account].add(_amount);
emit Transfer(address(0), _account, _amount);
}
function _burn(address _account, uint256 _amount) internal {
require(_account != address(0), "RewardTracker: burn from the zero address");
balances[_account] = balances[_account].sub(_amount, "RewardTracker: burn amount exceeds balance");
totalSupply = totalSupply.sub(_amount);
emit Transfer(_account, address(0), _amount);
}
function _transfer(address _sender, address _recipient, uint256 _amount) private {
require(_sender != address(0), "RewardTracker: transfer from the zero address");
require(_recipient != address(0), "RewardTracker: transfer to the zero address");
if (inPrivateTransferMode) { _validateHandler(); }
balances[_sender] = balances[_sender].sub(_amount, "RewardTracker: transfer amount exceeds balance");
balances[_recipient] = balances[_recipient].add(_amount);
emit Transfer(_sender, _recipient,_amount);
}
function _approve(address _owner, address _spender, uint256 _amount) private {
require(_owner != address(0), "RewardTracker: approve from the zero address");
require(_spender != address(0), "RewardTracker: approve to the zero address");
allowances[_owner][_spender] = _amount;
emit Approval(_owner, _spender, _amount);
}
function _validateHandler() private view {
require(isHandler[msg.sender], "RewardTracker: forbidden");
}
function _stake(address _fundingAccount, address _account, address _depositToken, uint256 _amount) private {
require(_amount > 0, "RewardTracker: invalid _amount");
require(isDepositToken[_depositToken], "RewardTracker: invalid _depositToken");
IERC20(_depositToken).safeTransferFrom(_fundingAccount, address(this), _amount);
_updateRewards(_account);
stakedAmounts[_account] = stakedAmounts[_account].add(_amount);
depositBalances[_account][_depositToken] = depositBalances[_account][_depositToken].add(_amount);
totalDepositSupply[_depositToken] = totalDepositSupply[_depositToken].add(_amount);
_mint(_account, _amount);
}
function _unstake(address _account, address _depositToken, uint256 _amount, address _receiver) private {
require(_amount > 0, "RewardTracker: invalid _amount");
require(isDepositToken[_depositToken], "RewardTracker: invalid _depositToken");
_updateRewards(_account);
uint256 stakedAmount = stakedAmounts[_account];
require(stakedAmounts[_account] >= _amount, "RewardTracker: _amount exceeds stakedAmount");
stakedAmounts[_account] = stakedAmount.sub(_amount);
uint256 depositBalance = depositBalances[_account][_depositToken];
require(depositBalance >= _amount, "RewardTracker: _amount exceeds depositBalance");
depositBalances[_account][_depositToken] = depositBalance.sub(_amount);
totalDepositSupply[_depositToken] = totalDepositSupply[_depositToken].sub(_amount);
_burn(_account, _amount);
IERC20(_depositToken).safeTransfer(_receiver, _amount);
}
function _updateRewards(address _account) private {
uint256 blockReward = IRewardDistributor(distributor).distribute();
uint256 supply = totalSupply;
uint256 _cumulativeRewardPerToken = cumulativeRewardPerToken;
if (supply > 0 && blockReward > 0) {
_cumulativeRewardPerToken = _cumulativeRewardPerToken.add(blockReward.mul(PRECISION).div(supply));
cumulativeRewardPerToken = _cumulativeRewardPerToken;
}
// cumulativeRewardPerToken can only increase
// so if cumulativeRewardPerToken is zero, it means there are no rewards yet
if (_cumulativeRewardPerToken == 0) {
return;
}
if (_account != address(0)) {
uint256 stakedAmount = stakedAmounts[_account];
uint256 accountReward = stakedAmount.mul(_cumulativeRewardPerToken.sub(previousCumulatedRewardPerToken[_account])).div(PRECISION);
uint256 _claimableReward = claimableReward[_account].add(accountReward);
claimableReward[_account] = _claimableReward;
previousCumulatedRewardPerToken[_account] = _cumulativeRewardPerToken;
if (_claimableReward > 0 && stakedAmounts[_account] > 0) {
uint256 nextCumulativeReward = cumulativeRewards[_account].add(accountReward);
averageStakedAmounts[_account] = averageStakedAmounts[_account].mul(cumulativeRewards[_account]).div(nextCumulativeReward)
.add(stakedAmount.mul(accountReward).div(nextCumulativeReward));
cumulativeRewards[_account] = nextCumulativeReward;
}
}
}
}