Contract Name:
VotingToken
Contract Source Code:
File 1 of 1 : VotingToken
pragma solidity ^0.5.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP. Does not include
* the optional functions; to access them see {ERC20Detailed}.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
/**
* @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 Standard math utilities missing in the Solidity language.
*/
library Math {
/**
* @dev Returns the largest of two numbers.
*/
function max(uint256 a, uint256 b) internal pure returns (uint256) {
return a >= b ? a : b;
}
/**
* @dev Returns the smallest of two numbers.
*/
function min(uint256 a, uint256 b) internal pure returns (uint256) {
return a < b ? a : b;
}
/**
* @dev Returns the average of two numbers. The result is rounded towards
* zero.
*/
function average(uint256 a, uint256 b) internal pure returns (uint256) {
// (a + b) / 2 can overflow, so we distribute
return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
}
}
/**
* @dev Collection of functions related to array types.
*/
library Arrays {
/**
* @dev Searches a sorted `array` and returns the first index that contains
* a value greater or equal to `element`. If no such index exists (i.e. all
* values in the array are strictly less than `element`), the array length is
* returned. Time complexity O(log n).
*
* `array` is expected to be sorted in ascending order, and to contain no
* repeated elements.
*/
function findUpperBound(uint256[] storage array, uint256 element) internal view returns (uint256) {
if (array.length == 0) {
return 0;
}
uint256 low = 0;
uint256 high = array.length;
while (low < high) {
uint256 mid = Math.average(low, high);
// Note that mid will always be strictly less than high (i.e. it will be a valid array index)
// because Math.average rounds down (it does integer division with truncation).
if (array[mid] > element) {
high = mid;
} else {
low = mid + 1;
}
}
// At this point `low` is the exclusive upper bound. We will return the inclusive upper bound.
if (low > 0 && array[low - 1] == element) {
return low - 1;
} else {
return low;
}
}
}
/**
* @title Counters
* @author Matt Condon (@shrugs)
* @dev Provides counters that can only be incremented or decremented by one. This can be used e.g. to track the number
* of elements in a mapping, issuing ERC721 ids, or counting request ids.
*
* Include with `using Counters for Counters.Counter;`
* Since it is not possible to overflow a 256 bit integer with increments of one, `increment` can skip the {SafeMath}
* overflow check, thereby saving gas. This does assume however correct usage, in that the underlying `_value` is never
* directly accessed.
*/
library Counters {
using SafeMath for uint256;
struct Counter {
// This variable should never be directly accessed by users of the library: interactions must be restricted to
// the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
// this feature: see https://github.com/ethereum/solidity/issues/4637
uint256 _value; // default: 0
}
function current(Counter storage counter) internal view returns (uint256) {
return counter._value;
}
function increment(Counter storage counter) internal {
counter._value += 1;
}
function decrement(Counter storage counter) internal {
counter._value = counter._value.sub(1);
}
}
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
contract Context {
// Empty internal constructor, to prevent people from mistakenly deploying
// an instance of this contract, which should be used via inheritance.
constructor () internal { }
// solhint-disable-previous-line no-empty-blocks
function _msgSender() internal view returns (address payable) {
return msg.sender;
}
function _msgData() internal view returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20Mintable}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin guidelines: functions revert instead
* of returning `false` on failure. This behavior is nonetheless conventional
* and does not conflict with the expectations of ERC20 applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20 {
using SafeMath for uint256;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20};
*
* Requirements:
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for `sender`'s tokens of at least
* `amount`.
*/
function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
return true;
}
/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(address sender, address recipient, uint256 amount) internal {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements
*
* - `to` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal {
require(account != address(0), "ERC20: mint to the zero address");
_totalSupply = _totalSupply.add(amount);
_balances[account] = _balances[account].add(amount);
emit Transfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal {
require(account != address(0), "ERC20: burn from the zero address");
_balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
*
* This is internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(address owner, address spender, uint256 amount) internal {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Destroys `amount` tokens from `account`.`amount` is then deducted
* from the caller's allowance.
*
* See {_burn} and {_approve}.
*/
function _burnFrom(address account, uint256 amount) internal {
_burn(account, amount);
_approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "ERC20: burn amount exceeds allowance"));
}
}
/**
* @title ERC20 token with snapshots.
* @dev Inspired by Jordi Baylina's
* https://github.com/Giveth/minimd/blob/ea04d950eea153a04c51fa510b068b9dded390cb/contracts/MiniMeToken.sol[MiniMeToken]
* to record historical balances.
*
* When a snapshot is made, the balances and total supply at the time of the snapshot are recorded for later
* access.
*
* To make a snapshot, call the {snapshot} function, which will emit the {Snapshot} event and return a snapshot id.
* To get the total supply from a snapshot, call the function {totalSupplyAt} with the snapshot id.
* To get the balance of an account from a snapshot, call the {balanceOfAt} function with the snapshot id and the
* account address.
* @author Validity Labs AG <[email protected]>
*/
contract ERC20Snapshot is ERC20 {
using SafeMath for uint256;
using Arrays for uint256[];
using Counters for Counters.Counter;
// Snapshotted values have arrays of ids and the value corresponding to that id. These could be an array of a
// Snapshot struct, but that would impede usage of functions that work on an array.
struct Snapshots {
uint256[] ids;
uint256[] values;
}
mapping (address => Snapshots) private _accountBalanceSnapshots;
Snapshots private _totalSupplySnapshots;
// Snapshot ids increase monotonically, with the first value being 1. An id of 0 is invalid.
Counters.Counter private _currentSnapshotId;
event Snapshot(uint256 id);
// Creates a new snapshot id. Balances are only stored in snapshots on demand: unless a snapshot was taken, a
// balance change will not be recorded. This means the extra added cost of storing snapshotted balances is only paid
// when required, but is also flexible enough that it allows for e.g. daily snapshots.
function snapshot() public returns (uint256) {
_currentSnapshotId.increment();
uint256 currentId = _currentSnapshotId.current();
emit Snapshot(currentId);
return currentId;
}
function balanceOfAt(address account, uint256 snapshotId) public view returns (uint256) {
(bool snapshotted, uint256 value) = _valueAt(snapshotId, _accountBalanceSnapshots[account]);
return snapshotted ? value : balanceOf(account);
}
function totalSupplyAt(uint256 snapshotId) public view returns(uint256) {
(bool snapshotted, uint256 value) = _valueAt(snapshotId, _totalSupplySnapshots);
return snapshotted ? value : totalSupply();
}
// _transfer, _mint and _burn are the only functions where the balances are modified, so it is there that the
// snapshots are updated. Note that the update happens _before_ the balance change, with the pre-modified value.
// The same is true for the total supply and _mint and _burn.
function _transfer(address from, address to, uint256 value) internal {
_updateAccountSnapshot(from);
_updateAccountSnapshot(to);
super._transfer(from, to, value);
}
function _mint(address account, uint256 value) internal {
_updateAccountSnapshot(account);
_updateTotalSupplySnapshot();
super._mint(account, value);
}
function _burn(address account, uint256 value) internal {
_updateAccountSnapshot(account);
_updateTotalSupplySnapshot();
super._burn(account, value);
}
// When a valid snapshot is queried, there are three possibilities:
// a) The queried value was not modified after the snapshot was taken. Therefore, a snapshot entry was never
// created for this id, and all stored snapshot ids are smaller than the requested one. The value that corresponds
// to this id is the current one.
// b) The queried value was modified after the snapshot was taken. Therefore, there will be an entry with the
// requested id, and its value is the one to return.
// c) More snapshots were created after the requested one, and the queried value was later modified. There will be
// no entry for the requested id: the value that corresponds to it is that of the smallest snapshot id that is
// larger than the requested one.
//
// In summary, we need to find an element in an array, returning the index of the smallest value that is larger if
// it is not found, unless said value doesn't exist (e.g. when all values are smaller). Arrays.findUpperBound does
// exactly this.
function _valueAt(uint256 snapshotId, Snapshots storage snapshots)
private view returns (bool, uint256)
{
require(snapshotId > 0, "ERC20Snapshot: id is 0");
// solhint-disable-next-line max-line-length
require(snapshotId <= _currentSnapshotId.current(), "ERC20Snapshot: nonexistent id");
uint256 index = snapshots.ids.findUpperBound(snapshotId);
if (index == snapshots.ids.length) {
return (false, 0);
} else {
return (true, snapshots.values[index]);
}
}
function _updateAccountSnapshot(address account) private {
_updateSnapshot(_accountBalanceSnapshots[account], balanceOf(account));
}
function _updateTotalSupplySnapshot() private {
_updateSnapshot(_totalSupplySnapshots, totalSupply());
}
function _updateSnapshot(Snapshots storage snapshots, uint256 currentValue) private {
uint256 currentId = _currentSnapshotId.current();
if (_lastSnapshotId(snapshots.ids) < currentId) {
snapshots.ids.push(currentId);
snapshots.values.push(currentValue);
}
}
function _lastSnapshotId(uint256[] storage ids) private view returns (uint256) {
if (ids.length == 0) {
return 0;
} else {
return ids[ids.length - 1];
}
}
}
/**
* @title ERC20 interface that includes burn and mint methods.
*/
contract ExpandedIERC20 is IERC20 {
/**
* @notice Burns a specific amount of the caller's tokens.
* @dev Only burns the caller's tokens, so it is safe to leave this method permissionless.
*/
function burn(uint value) external;
/**
* @notice Mints tokens and adds them to the balance of the `to` address.
* @dev This method should be permissioned to only allow designated parties to mint tokens.
*/
function mint(address to, uint value) external returns (bool);
}
library Exclusive {
struct RoleMembership {
address member;
}
function isMember(RoleMembership storage roleMembership, address memberToCheck) internal view returns (bool) {
return roleMembership.member == memberToCheck;
}
function resetMember(RoleMembership storage roleMembership, address newMember) internal {
require(newMember != address(0x0), "Cannot set an exclusive role to 0x0");
roleMembership.member = newMember;
}
function getMember(RoleMembership storage roleMembership) internal view returns (address) {
return roleMembership.member;
}
function init(RoleMembership storage roleMembership, address initialMember) internal {
resetMember(roleMembership, initialMember);
}
}
library Shared {
struct RoleMembership {
mapping(address => bool) members;
}
function isMember(RoleMembership storage roleMembership, address memberToCheck) internal view returns (bool) {
return roleMembership.members[memberToCheck];
}
function addMember(RoleMembership storage roleMembership, address memberToAdd) internal {
roleMembership.members[memberToAdd] = true;
}
function removeMember(RoleMembership storage roleMembership, address memberToRemove) internal {
roleMembership.members[memberToRemove] = false;
}
function init(RoleMembership storage roleMembership, address[] memory initialMembers) internal {
for (uint i = 0; i < initialMembers.length; i++) {
addMember(roleMembership, initialMembers[i]);
}
}
}
/**
* @title Base class to manage permissions for the derived class.
*/
contract MultiRole {
using Exclusive for Exclusive.RoleMembership;
using Shared for Shared.RoleMembership;
enum RoleType { Invalid, Exclusive, Shared }
struct Role {
uint managingRole;
RoleType roleType;
Exclusive.RoleMembership exclusiveRoleMembership;
Shared.RoleMembership sharedRoleMembership;
}
mapping(uint => Role) private roles;
/**
* @notice Reverts unless the caller is a member of the specified roleId.
*/
modifier onlyRoleHolder(uint roleId) {
require(holdsRole(roleId, msg.sender), "Sender does not hold required role");
_;
}
/**
* @notice Reverts unless the caller is a member of the manager role for the specified roleId.
*/
modifier onlyRoleManager(uint roleId) {
require(holdsRole(roles[roleId].managingRole, msg.sender), "Can only be called by a role manager");
_;
}
/**
* @notice Reverts unless the roleId represents an initialized, exclusive roleId.
*/
modifier onlyExclusive(uint roleId) {
require(roles[roleId].roleType == RoleType.Exclusive, "Must be called on an initialized Exclusive role");
_;
}
/**
* @notice Reverts unless the roleId represents an initialized, shared roleId.
*/
modifier onlyShared(uint roleId) {
require(roles[roleId].roleType == RoleType.Shared, "Must be called on an initialized Shared role");
_;
}
/**
* @notice Whether `memberToCheck` is a member of roleId.
* @dev Reverts if roleId does not correspond to an initialized role.
*/
function holdsRole(uint roleId, address memberToCheck) public view returns (bool) {
Role storage role = roles[roleId];
if (role.roleType == RoleType.Exclusive) {
return role.exclusiveRoleMembership.isMember(memberToCheck);
} else if (role.roleType == RoleType.Shared) {
return role.sharedRoleMembership.isMember(memberToCheck);
}
require(false, "Invalid roleId");
}
/**
* @notice Changes the exclusive role holder of `roleId` to `newMember`.
* @dev Reverts if the caller is not a member of the managing role for `roleId` or if `roleId` is not an
* initialized, exclusive role.
*/
function resetMember(uint roleId, address newMember) public onlyExclusive(roleId) onlyRoleManager(roleId) {
roles[roleId].exclusiveRoleMembership.resetMember(newMember);
}
/**
* @notice Gets the current holder of the exclusive role, `roleId`.
* @dev Reverts if `roleId` does not represent an initialized, exclusive role.
*/
function getMember(uint roleId) public view onlyExclusive(roleId) returns (address) {
return roles[roleId].exclusiveRoleMembership.getMember();
}
/**
* @notice Adds `newMember` to the shared role, `roleId`.
* @dev Reverts if `roleId` does not represent an initialized, shared role or if the caller is not a member of the
* managing role for `roleId`.
*/
function addMember(uint roleId, address newMember) public onlyShared(roleId) onlyRoleManager(roleId) {
roles[roleId].sharedRoleMembership.addMember(newMember);
}
/**
* @notice Removes `memberToRemove` from the shared role, `roleId`.
* @dev Reverts if `roleId` does not represent an initialized, shared role or if the caller is not a member of the
* managing role for `roleId`.
*/
function removeMember(uint roleId, address memberToRemove) public onlyShared(roleId) onlyRoleManager(roleId) {
roles[roleId].sharedRoleMembership.removeMember(memberToRemove);
}
/**
* @notice Reverts if `roleId` is not initialized.
*/
modifier onlyValidRole(uint roleId) {
require(roles[roleId].roleType != RoleType.Invalid, "Attempted to use an invalid roleId");
_;
}
/**
* @notice Reverts if `roleId` is initialized.
*/
modifier onlyInvalidRole(uint roleId) {
require(roles[roleId].roleType == RoleType.Invalid, "Cannot use a pre-existing role");
_;
}
/**
* @notice Internal method to initialize a shared role, `roleId`, which will be managed by `managingRoleId`.
* `initialMembers` will be immediately added to the role.
* @dev Should be called by derived contracts, usually at construction time. Will revert if the role is already
* initialized.
*/
function _createSharedRole(uint roleId, uint managingRoleId, address[] memory initialMembers)
internal
onlyInvalidRole(roleId)
{
Role storage role = roles[roleId];
role.roleType = RoleType.Shared;
role.managingRole = managingRoleId;
role.sharedRoleMembership.init(initialMembers);
require(roles[managingRoleId].roleType != RoleType.Invalid,
"Attempted to use an invalid role to manage a shared role");
}
/**
* @notice Internal method to initialize a exclusive role, `roleId`, which will be managed by `managingRoleId`.
* `initialMembers` will be immediately added to the role.
* @dev Should be called by derived contracts, usually at construction time. Will revert if the role is already
* initialized.
*/
function _createExclusiveRole(uint roleId, uint managingRoleId, address initialMember)
internal
onlyInvalidRole(roleId)
{
Role storage role = roles[roleId];
role.roleType = RoleType.Exclusive;
role.managingRole = managingRoleId;
role.exclusiveRoleMembership.init(initialMember);
require(roles[managingRoleId].roleType != RoleType.Invalid,
"Attempted to use an invalid role to manage an exclusive role");
}
}
/**
* @title Ownership of this token allows a voter to respond to price requests.
* @dev Supports snapshotting and allows the Oracle to mint new tokens as rewards.
*/
contract VotingToken is ExpandedIERC20, ERC20Snapshot, MultiRole {
enum Roles {
// Can set the minter and burner.
Owner,
// Addresses that can mint new tokens.
Minter,
// Addresses that can burn tokens that address owns.
Burner
}
// Standard ERC20 metadata.
string public constant name = "UMA Voting Token v1"; // solhint-disable-line const-name-snakecase
string public constant symbol = "UMA"; // solhint-disable-line const-name-snakecase
uint8 public constant decimals = 18; // solhint-disable-line const-name-snakecase
constructor() public {
_createExclusiveRole(uint(Roles.Owner), uint(Roles.Owner), msg.sender);
_createSharedRole(uint(Roles.Minter), uint(Roles.Owner), new address[](0));
_createSharedRole(uint(Roles.Burner), uint(Roles.Owner), new address[](0));
}
/**
* @dev Mints `value` tokens to `recipient`, returning true on success.
*/
function mint(address recipient, uint value) external onlyRoleHolder(uint(Roles.Minter)) returns (bool) {
_mint(recipient, value);
return true;
}
/**
* @dev Burns `value` tokens owned by `msg.sender`.
*/
function burn(uint value) external onlyRoleHolder(uint(Roles.Burner)) {
_burn(msg.sender, value);
}
}