// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
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 in 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");
return _functionCallWithValue(target, data, value, errorMessage);
}
function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
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);
}
}
}
}
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);
}
/**
* @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");
}
}
}
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;
}
}
interface IStakedDVF {
function balanceOf(address account) external view returns (uint);
function transfer(address dst, uint rawAmount) external returns (bool);
function enter(uint256 _amount) external returns (bool);
function leave(uint256 _share) external returns (bool);
function takeVoteSnapshotAtBlock() external returns (uint);
function balanceOfAt(address account, uint256 snapshotId) external view returns (uint);
}
/**
* @title SupporterVester
* @dev A token holder contract that can release its token balance gradually like a
* typical vesting scheme, with a cliff and vesting period.
*/
contract SupporterVester {
using SafeMath for uint256;
using SafeERC20 for IERC20;
event TokensReleased(address token, uint256 amount);
// beneficiary of tokens after they are released
address private _beneficiary;
address public _delegateForVoting;
modifier onlyBeneficiary() {
require (msg.sender == _beneficiary);
_;
}
IERC20 public _dvf;
IStakedDVF public _xdvf;
// Durations and timestamps are expressed in UNIX time, the same units as block.timestamp.
uint256 private _cliff;
uint256 private _start;
uint256 private _duration;
uint256 private _released;
/**
* @dev Creates a vesting contract that vests its balance of any ERC20 token to the
* beneficiary, gradually in a linear fashion until start + duration. By then all
* of the balance will have vested.
* @param vestingBeneficiary address of the beneficiary to whom vested tokens are transferred
* @param cliffDuration duration in seconds of the cliff in which tokens will begin to vest
* @param vestingStart the time (as Unix time) at which point vesting starts
* @param vestingDuration duration in seconds of the period in which the tokens will vest
*/
constructor (
address dvf,
address xdvf,
address vestingBeneficiary,
uint256 vestingStart,
uint256 cliffDuration,
uint256 vestingDuration) public {
require(vestingBeneficiary != address(0), "Vesting: beneficiary is the zero address");
// solhint-disable-next-line max-line-length
require(cliffDuration <= vestingDuration, "Vesting: cliff is longer than duration");
require(vestingDuration > 0, "Vesting: duration is 0");
// solhint-disable-next-line max-line-length
require(vestingStart.add(vestingDuration) > block.timestamp, "Vesting: final time is before current time");
_beneficiary = vestingBeneficiary;
_duration = vestingDuration;
_cliff = vestingStart.add(cliffDuration);
_start = vestingStart;
_dvf = IERC20(dvf);
_xdvf = IStakedDVF(xdvf);
}
/**
* @return the beneficiary of the tokens.
*/
function beneficiary() public view returns (address) {
return _beneficiary;
}
/**
* @return the nominated delegate who can vote on behalf of beneficiary
*/
function delegateForVoting() public view returns (address) {
if (_delegateForVoting != address(0)) return _delegateForVoting;
return _beneficiary;
}
/**
* @return the cliff time of the token vesting.
*/
function cliff() public view returns (uint256) {
return _cliff;
}
/**
* @return the start time of the token vesting.
*/
function start() public view returns (uint256) {
return _start;
}
/**
* @return the duration of the token vesting.
*/
function duration() public view returns (uint256) {
return _duration;
}
/**
* @return the amount of the token released.
*/
function released() public view returns (uint256) {
return _released;
}
/**
* @notice Transfers vested tokens to beneficiary.
*/
function release() public {
uint256 unreleased = _releasableAmount();
require(unreleased > 0, "Vesting: no tokens are due");
_released = _released.add(unreleased);
_dvf.safeTransfer(_beneficiary, unreleased);
emit TokensReleased(address(_dvf), unreleased);
}
/**
* @dev Calculates the amount that has already vested but hasn't been released yet.
*/
function _releasableAmount() private view returns (uint256) {
return _vestedAmount().sub(_released);
}
/**
* @dev Calculates the amount that has already vested.
*/
function _vestedAmount() private view returns (uint256) {
uint256 currentBalance = _dvf.balanceOf(address(this));
uint256 totalBalance = currentBalance.add(_released);
if (block.timestamp < _cliff) {
return 0;
} else if (block.timestamp >= _start.add(_duration)) {
return totalBalance;
} else {
return totalBalance.mul(block.timestamp.sub(_start)).div(_duration);
}
}
/**
* @notice Stakes the tokens in the vesting contract on behalf of beneficiary.
*/
function stake() onlyBeneficiary public {
uint256 currentBalance = _dvf.balanceOf(address(this));
require(currentBalance > 0, "Vesting: No unstaked tokens");
_dvf.approve(address(_xdvf), currentBalance);
_xdvf.enter(currentBalance);
}
/**
* @notice Unstakes the tokens in the vesting contract on behalf of beneficiary.
*/
function unstake() onlyBeneficiary public {
uint256 currentBalance = _xdvf.balanceOf(address(this));
require(currentBalance > 0, "Vesting: No staked tokens");
_xdvf.leave(currentBalance);
}
function unstakeAndRelease() onlyBeneficiary public {
unstake();
release();
}
function nominateDelegate(address _newDelegate) onlyBeneficiary public {
_delegateForVoting = _newDelegate;
}
}
{
"compilationTarget": {
"SupporterVester.sol": "SupporterVester"
},
"evmVersion": "istanbul",
"libraries": {},
"metadata": {
"bytecodeHash": "ipfs"
},
"optimizer": {
"enabled": true,
"runs": 10000
},
"remappings": []
}
[{"inputs":[{"internalType":"address","name":"dvf","type":"address"},{"internalType":"address","name":"xdvf","type":"address"},{"internalType":"address","name":"vestingBeneficiary","type":"address"},{"internalType":"uint256","name":"vestingStart","type":"uint256"},{"internalType":"uint256","name":"cliffDuration","type":"uint256"},{"internalType":"uint256","name":"vestingDuration","type":"uint256"}],"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"token","type":"address"},{"indexed":false,"internalType":"uint256","name":"amount","type":"uint256"}],"name":"TokensReleased","type":"event"},{"inputs":[],"name":"_delegateForVoting","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"_dvf","outputs":[{"internalType":"contract IERC20","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"_xdvf","outputs":[{"internalType":"contract IStakedDVF","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"beneficiary","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"cliff","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"delegateForVoting","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"duration","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"_newDelegate","type":"address"}],"name":"nominateDelegate","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"release","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"released","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"stake","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"start","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"unstake","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[],"name":"unstakeAndRelease","outputs":[],"stateMutability":"nonpayable","type":"function"}]