Contract Name:
StakingToken
Contract Source Code:
File 1 of 1 : StakingToken
// File: @openzeppelin/contracts/math/SafeMath.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
/**
* @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.
*/
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;
}
}
// File: @openzeppelin/contracts/utils/Address.sol
pragma solidity ^0.6.2;
/**
* @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 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);
}
}
}
}
// File: @openzeppelin/contracts/token/ERC20/IERC20.sol
pragma solidity ^0.6.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount)
external
returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender)
external
view
returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address sender,
address recipient,
uint256 amount
) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(
address indexed owner,
address indexed spender,
uint256 value
);
}
// File: @openzeppelin/contracts/GSN/Context.sol
pragma solidity ^0.6.0;
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol
pragma solidity ^0.6.0;
/**
* @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 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"
);
}
}
}
// File: @openzeppelin/contracts/utils/ReentrancyGuard.sol
pragma solidity ^0.6.0;
/**
* @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;
}
}
// File: contracts/Interface.sol
pragma solidity >=0.6.0 <0.7.0;
interface IERC20Mint {
function mint(uint256 amount) external returns (bool);
}
interface IERC20MintTo {
function mint_to(address to, uint256 amount) external returns (bool);
}
// Dada Token
interface IReserveToken {
function reserve_from(address who, uint256 amount) external returns (bool);
function unreserve_from(address who, uint256 amount)
external
returns (bool);
}
interface IShareModule {
function ops_reward(
address to,
uint256 amount,
uint256 ops_type,
uint256 term
) external returns (uint256);
}
interface IInterestModule {
function get(
uint256 amount,
uint256 term,
uint256 how_long
) external returns (uint256);
}
interface IStakeModule {
function is_proper_term(uint256 n_days) external pure returns (bool);
function get_proper_term()
external
pure
returns (uint256[] memory proper_terms);
}
// File: contracts/StakingToken.sol
pragma solidity >=0.6.0 <0.7.0;
// import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
// import "@openzeppelin/contracts/token/ERC20/ERC20Capped.sol";
contract StakingToken is Context, IERC20, ReentrancyGuard {
using Address for address;
using SafeMath for uint256;
using SafeERC20 for IERC20;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
uint256 private _cap;
uint256 private _softcap;
address private _owner; // the supervisor with total authority
address private _mint_account; // account which is allowed to mint new tokens
uint256 public epoch; // the timestamp this token becomes alive
uint256 public constant month = 30 * 86400;
mapping(address => uint256) internal _balances;
mapping(address => uint256) internal _reserved_balances;
mapping(address => mapping(address => uint256)) internal _allowances;
/// @notice A record of each accounts delegate
mapping(address => address) public delegates;
/// @notice A checkpoint for marking number of votes from a given block
struct Checkpoint {
uint256 fromBlock;
uint256 votes;
}
/// @notice A record of votes checkpoints for each account, by index
mapping(address => mapping(uint256 => Checkpoint)) public checkpoints;
/// @notice The number of checkpoints for each account
mapping(address => uint256) public numCheckpoints;
event BalanceReserved(address who, uint256 amount);
event BalanceUnreserved(address who, uint256 amount);
/// @notice An event thats emitted when an account changes its delegate
event DelegateChanged(
address indexed delegator,
address indexed fromDelegate,
address indexed toDelegate
);
/// @notice An event thats emitted when a delegate account's vote balance changes
event DelegateVotesChanged(
address indexed delegate,
uint256 previousBalance,
uint256 newBalance
);
constructor(
string memory name,
string memory symbol,
uint256 softcap,
uint256 cap
) public {
_mint_account = _msgSender();
_owner = _msgSender();
_name = name;
_symbol = symbol;
_decimals = 18;
_softcap = softcap;
_cap = cap;
}
modifier isAlive {
require(epoch > 0 && block.timestamp > epoch);
_;
}
modifier owner_only {
require(_msgSender() == _owner, "StakingToken: Owner only");
_;
}
modifier mint_auth_required {
require(
_msgSender() == _mint_account || _msgSender() == _owner,
"StakingToken: Invalid mint request"
);
_;
}
function transfer_ownership(address new_owner)
public
owner_only
nonReentrant
{
_owner = new_owner;
}
function owner() public view returns (address) {
return _owner;
}
function set_epoch(uint256 ts) public owner_only nonReentrant {
epoch = ts;
}
function mint_account() public view returns (address) {
return _mint_account;
}
function name() public view returns (string memory) {
return _name;
}
function symbol() public view returns (string memory) {
return _symbol;
}
function decimals() public view returns (uint8) {
return _decimals;
}
function totalSupply() public view override returns (uint256) {
return _totalSupply;
}
function cap() public view returns (uint256) {
return _cap;
}
function softCap() public view returns (uint256) {
return _softcap;
}
function setSoftCap(uint256 n) public owner_only nonReentrant {
require(n <= _cap, "StakingToken: softcap overflows cap");
require(
n >= _totalSupply,
"StakingToken: softcap must be higher than total supply"
);
_softcap = n;
}
function balanceOf(address account)
public
view
override
returns (uint256 free)
{
return _balances[account];
}
function transfer(address recipient, uint256 amount)
public
virtual
override
nonReentrant
returns (bool)
{
_transfer(_msgSender(), recipient, amount);
return true;
}
function allowance(address account_owner, address spender)
public
view
virtual
override
returns (uint256)
{
return _allowances[account_owner][spender];
}
function approve(address spender, uint256 amount)
public
virtual
override
nonReentrant
returns (bool)
{
_approve(_msgSender(), spender, amount);
return true;
}
function transferFrom(
address sender,
address recipient,
uint256 amount
) public virtual override nonReentrant returns (bool) {
_transfer(sender, recipient, amount);
_approve(
sender,
_msgSender(),
_allowances[sender][_msgSender()].sub(
amount,
"ERC20: transfer amount exceeds allowance"
)
);
return true;
}
function increaseAllowance(address spender, uint256 addedValue)
public
virtual
nonReentrant
returns (bool)
{
_approve(
_msgSender(),
spender,
_allowances[_msgSender()][spender].add(addedValue)
);
return true;
}
function decreaseAllowance(address spender, uint256 subtractedValue)
public
virtual
nonReentrant
returns (bool)
{
_approve(
_msgSender(),
spender,
_allowances[_msgSender()][spender].sub(
subtractedValue,
"ERC20: decreased allowance below zero"
)
);
return true;
}
function mint(uint256 amount)
public
virtual
nonReentrant
mint_auth_required
returns (bool)
{
_mint(_msgSender(), amount);
return true;
}
function burn(uint256 amount) public virtual nonReentrant returns (bool) {
_burn(_msgSender(), amount);
return true;
}
function burnFrom(address account, uint256 amount)
public
virtual
nonReentrant
{
uint256 decreasedAllowance =
allowance(account, _msgSender()).sub(
amount,
"ERC20: burn amount exceeds allowance"
);
_approve(account, _msgSender(), decreasedAllowance);
_burn(account, amount);
}
function _transfer(
address sender,
address recipient,
uint256 amount
) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
_balances[sender] = _balances[sender].sub(
amount,
"ERC20: transfer amount exceeds balance"
);
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
_afterTokenTransfer(sender, recipient, amount);
}
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
_afterTokenTransfer(address(0), account, amount);
}
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
_balances[account] = _balances[account].sub(
amount,
"ERC20: burn amount exceeds balance"
);
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
function _approve(
address account_owner,
address spender,
uint256 amount
) internal virtual {
require(
account_owner != address(0),
"ERC20: approve from the zero address"
);
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[account_owner][spender] = amount;
emit Approval(account_owner, spender, amount);
}
function _setupDecimals(uint8 decimals_) internal {
_decimals = decimals_;
}
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {
if (from == address(0)) {
// When minting tokens
uint256 newSupply = totalSupply().add(amount);
require(
newSupply <= _softcap && newSupply <= _cap,
"ERC20Capped: cap exceeded"
);
}
}
function _afterTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {
_moveDelegates(from, to, amount);
}
// end of ERC20 implementation
function _reserve(address who, uint256 amount) internal returns (bool) {
// make sure 'who' has enough tokens in his pocket
require(
_balances[who] >= amount,
"StakingToken: user's free balance is not enough"
);
// move from balance into reserved_balance
_balances[who] = _balances[who].sub(amount);
_reserved_balances[who] = _reserved_balances[who].add(amount);
emit BalanceReserved(who, amount);
return true;
}
function _unreserve(address who, uint256 amount) internal returns (bool) {
require(
_reserved_balances[who] >= amount,
"StakingToken: not enough reserved balance"
);
// move from reserved_balance into balance
_reserved_balances[who] = _reserved_balances[who].sub(amount);
_balances[who] = _balances[who].add(amount);
emit BalanceUnreserved(who, amount);
return true;
}
function reservedOf(address account) public view returns (uint256) {
return _reserved_balances[account];
}
function actualBalanceOf(address account)
public
view
returns (uint256 free_balance, uint256 reserved_balance)
{
return (_balances[account], _reserved_balances[account]);
}
function reserve_from(address who, uint256 amount)
public
mint_auth_required
nonReentrant
returns (bool)
{
return _reserve(who, amount);
}
function unreserve_from(address who, uint256 amount)
public
mint_auth_required
nonReentrant
returns (bool)
{
return _unreserve(who, amount);
}
function set_mint_account(address account) public owner_only nonReentrant {
_mint_account = account;
}
function _moveDelegates(
address srcRep,
address dstRep,
uint256 amount
) internal {
if (srcRep != dstRep && amount > 0) {
if (srcRep != address(0)) {
uint256 srcRepNum = numCheckpoints[srcRep];
uint256 srcRepOld =
srcRepNum > 0
? checkpoints[srcRep][srcRepNum - 1].votes
: 0;
uint256 srcRepNew = srcRepOld.sub(amount);
_writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);
}
if (dstRep != address(0)) {
uint256 dstRepNum = numCheckpoints[dstRep];
uint256 dstRepOld =
dstRepNum > 0
? checkpoints[dstRep][dstRepNum - 1].votes
: 0;
uint256 dstRepNew = dstRepOld.add(amount);
_writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);
}
}
}
function _writeCheckpoint(
address delegatee,
uint256 nCheckpoints,
uint256 oldVotes,
uint256 newVotes
) internal {
if (
nCheckpoints > 0 &&
checkpoints[delegatee][nCheckpoints - 1].fromBlock == block.number
) {
checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;
} else {
checkpoints[delegatee][nCheckpoints] = Checkpoint(
block.number,
newVotes
);
numCheckpoints[delegatee] = nCheckpoints + 1;
}
emit DelegateVotesChanged(delegatee, oldVotes, newVotes);
}
function getChainId() internal pure returns (uint256) {
uint256 chainId;
assembly {
chainId := chainid()
}
return chainId;
}
/**
* @notice Delegate votes from `msg.sender` to `delegatee`
* @param delegatee The address to delegate votes to
*/
function delegate(address delegatee) public nonReentrant {
return _delegate(msg.sender, delegatee);
}
/**
* @notice Gets the current votes balance for `account`
* @param account The address to get votes balance
* @return The number of current votes for `account`
*/
function getCurrentVotes(address account) external view returns (uint256) {
uint256 nCheckpoints = numCheckpoints[account];
return
nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;
}
/**
* @notice Determine the prior number of votes for an account as of a block number
* @dev Block number must be a finalized block or else this function will revert to prevent misinformation.
* @param account The address of the account to check
* @param blockNumber The block number to get the vote balance at
* @return The number of votes the account had as of the given block
*/
function getPriorVotes(address account, uint256 blockNumber)
public
view
returns (uint256)
{
require(blockNumber < block.number, "StakingToken: not yet determined");
uint256 nCheckpoints = numCheckpoints[account];
if (nCheckpoints == 0) {
return 0;
}
// First check most recent balance
if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {
return checkpoints[account][nCheckpoints - 1].votes;
}
// Next check implicit zero balance
if (checkpoints[account][0].fromBlock > blockNumber) {
return 0;
}
uint256 lower = 0;
uint256 upper = nCheckpoints - 1;
while (upper > lower) {
uint256 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
Checkpoint memory cp = checkpoints[account][center];
if (cp.fromBlock == blockNumber) {
return cp.votes;
} else if (cp.fromBlock < blockNumber) {
lower = center;
} else {
upper = center - 1;
}
}
return checkpoints[account][lower].votes;
}
function _delegate(address delegator, address delegatee) internal {
address currentDelegate = delegates[delegator];
uint256 delegatorBalance = _balances[delegator];
delegates[delegator] = delegatee;
emit DelegateChanged(delegator, currentDelegate, delegatee);
_moveDelegates(currentDelegate, delegatee, delegatorBalance);
}
function mint_and_lock(
address to_whom,
uint256 amount,
uint256 lockspan,
uint256 frozen_hell
) public mint_auth_required nonReentrant {
require(llocks[to_whom].remains_in_lock == 0);
LinearLockWithFrozenHell storage lk = llocks[to_whom];
lk.total_amount = amount;
lk.lock_span = lockspan;
lk.frozen_hell = frozen_hell;
lk.created_timestamp = block.timestamp;
lk.remains_in_lock = amount;
lk.latest_claim = block.timestamp;
_mint(address(this), amount);
_transferToReserved(address(this), to_whom, amount);
}
function can_claim() public view isAlive returns (uint256) {
if (_reserved_balances[_msgSender()] == 0) {
return 0;
}
if (llocks[_msgSender()].remains_in_lock == 0) {
return 0;
}
LinearLockWithFrozenHell storage llwf = llocks[_msgSender()];
uint256 begins = _releaseBegins(_msgSender());
if (block.timestamp < begins) {
return 0;
}
uint256 released_span = block.timestamp - begins;
uint256 delta = 1;
if (llwf.latest_claim > begins) {
released_span = block.timestamp - llwf.latest_claim;
delta = 0;
}
released_span = released_span.div(month);
if (released_span <= 0) {
return 0;
}
uint256 lock_span = llwf.lock_span.div(month);
uint256 released_amount =
llwf.total_amount.div(lock_span).mul(released_span) +
(lock_span - 1) *
delta;
return released_amount;
}
function claim() public nonReentrant isAlive {
require(
_reserved_balances[_msgSender()] > 0,
"StakingToken::claim: sender has no reserved balance"
);
require(
llocks[_msgSender()].remains_in_lock > 0,
"StakingToken::claim: sender has no locks"
);
LinearLockWithFrozenHell storage llwf = llocks[_msgSender()];
uint256 begins = _releaseBegins(_msgSender());
require(
block.timestamp > begins,
"StakingToken::claim: release has not begin yet"
);
uint256 released_span = block.timestamp - begins;
uint256 delta = 1;
if (llwf.latest_claim > begins) {
released_span = block.timestamp - llwf.latest_claim;
begins = llwf.latest_claim;
delta = 0;
}
released_span = released_span.div(month);
require(
released_span > 0,
"StakingToken: monthly release is not ready"
);
uint256 lock_span = llwf.lock_span.div(month);
uint256 released_amount =
llwf.total_amount.div(lock_span).mul(released_span) +
(lock_span - 1) *
delta;
if (llwf.remains_in_lock <= released_amount) {
released_amount = llwf.remains_in_lock;
llwf.remains_in_lock = 0;
} else {
llwf.remains_in_lock = llwf.remains_in_lock.sub(released_amount);
}
llwf.latest_claim = released_span * month + begins;
_unreserve(_msgSender(), released_amount);
}
struct LinearLockWithFrozenHell {
uint256 total_amount;
uint256 lock_span;
uint256 frozen_hell;
uint256 latest_claim;
uint256 created_timestamp;
uint256 remains_in_lock;
}
mapping(address => LinearLockWithFrozenHell) public llocks;
function _transferToReserved(
address sender,
address recipient,
uint256 amount
) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
_balances[sender] = _balances[sender].sub(
amount,
"ERC20: transfer amount exceeds balance"
);
_reserved_balances[recipient] = _reserved_balances[recipient].add(
amount
);
emit Transfer(sender, recipient, amount);
emit BalanceReserved(recipient, amount);
_afterTokenTransfer(sender, recipient, amount);
}
function _releaseBegins(address who) internal view returns (uint256) {
LinearLockWithFrozenHell storage llwf = llocks[who];
uint256 begins = 0;
if (llwf.created_timestamp > epoch) {
begins = llwf.created_timestamp;
} else {
begins = epoch;
}
if (llwf.frozen_hell > 0) {
begins = begins.add(llwf.frozen_hell);
}
return begins;
}
}