Contract Source Code:
File 1 of 1 : DydxToken
// SPDX-License-Identifier: AGPL-3.0
// File contracts/dependencies/open-zeppelin/Context.sol
pragma solidity 0.7.5;
/*
* @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 contracts/dependencies/open-zeppelin/IERC20.sol
pragma solidity 0.7.5;
/**
* @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 contracts/dependencies/open-zeppelin/SafeMath.sol
pragma solidity 0.7.5;
/**
* @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) {
// 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.
*/
function mod(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
// File contracts/dependencies/open-zeppelin/Address.sol
pragma solidity 0.7.5;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// According to EIP-1052, 0x0 is the value returned for not-yet created accounts
// and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
// for accounts without code, i.e. `keccak256('')`
bytes32 codehash;
bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
// solhint-disable-next-line no-inline-assembly
assembly {
codehash := extcodehash(account)
}
return (codehash != accountHash && codehash != 0x0);
}
/**
* @dev 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');
}
}
// File contracts/dependencies/open-zeppelin/ERC20.sol
pragma solidity ^0.7.5;
/**
* @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 {ERC20PresetMinterPauser}.
*
* 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;
using Address for address;
mapping (address => uint256) private _balances;
mapping (address => mapping (address => uint256)) private _allowances;
uint256 private _totalSupply;
string internal _name;
string internal _symbol;
uint8 private _decimals;
/**
* @dev Sets the values for {name} and {symbol}, initializes {decimals} with
* a default value of 18.
*
* To select a different value for {decimals}, use {_setupDecimals}.
*
* All three of these values are immutable: they can only be set once during
* construction.
*/
constructor (string memory name, string memory symbol) public {
_name = name;
_symbol = symbol;
_decimals = 18;
}
/**
* @dev Returns the name of the token.
*/
function name() virtual public view returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() virtual public view returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5,05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
* called.
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() virtual public view returns (uint8) {
return _decimals;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view override 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 virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override 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 virtual override 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 virtual 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 virtual 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 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);
}
/** @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 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);
}
/**
* @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 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);
}
/**
* @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 virtual {
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 Sets {decimals} to a value other than the default one of 18.
*
* WARNING: This function should only be called from the constructor. Most
* applications that interact with token contracts will not expect
* {decimals} to ever change, and may work incorrectly if it does.
*/
function _setupDecimals(uint8 decimals_) internal {
_decimals = decimals_;
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be to transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}
// File contracts/dependencies/open-zeppelin/Ownable.sol
pragma solidity 0.7.5;
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(_owner == _msgSender(), 'Ownable: caller is not the owner');
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), 'Ownable: new owner is the zero address');
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
// File contracts/interfaces/IGovernancePowerDelegationERC20.sol
pragma solidity 0.7.5;
interface IGovernancePowerDelegationERC20 {
enum DelegationType {
VOTING_POWER,
PROPOSITION_POWER
}
/**
* @dev Emitted when a user delegates governance power to another user.
*
* @param delegator The delegator.
* @param delegatee The delegatee.
* @param delegationType The type of delegation (VOTING_POWER, PROPOSITION_POWER).
*/
event DelegateChanged(
address indexed delegator,
address indexed delegatee,
DelegationType delegationType
);
/**
* @dev Emitted when an action changes the delegated power of a user.
*
* @param user The user whose delegated power has changed.
* @param amount The new amount of delegated power for the user.
* @param delegationType The type of delegation (VOTING_POWER, PROPOSITION_POWER).
*/
event DelegatedPowerChanged(address indexed user, uint256 amount, DelegationType delegationType);
/**
* @dev Delegates a specific governance power to a delegatee.
*
* @param delegatee The address to delegate power to.
* @param delegationType The type of delegation (VOTING_POWER, PROPOSITION_POWER).
*/
function delegateByType(address delegatee, DelegationType delegationType) external virtual;
/**
* @dev Delegates all governance powers to a delegatee.
*
* @param delegatee The user to which the power will be delegated.
*/
function delegate(address delegatee) external virtual;
/**
* @dev Returns the delegatee of an user.
*
* @param delegator The address of the delegator.
* @param delegationType The type of delegation (VOTING_POWER, PROPOSITION_POWER).
*/
function getDelegateeByType(address delegator, DelegationType delegationType)
external
view
virtual
returns (address);
/**
* @dev Returns the current delegated power of a user. The current power is the power delegated
* at the time of the last snapshot.
*
* @param user The user whose power to query.
* @param delegationType The type of power (VOTING_POWER, PROPOSITION_POWER).
*/
function getPowerCurrent(address user, DelegationType delegationType)
external
view
virtual
returns (uint256);
/**
* @dev Returns the delegated power of a user at a certain block.
*
* @param user The user whose power to query.
* @param blockNumber The block number at which to get the user's power.
* @param delegationType The type of power (VOTING_POWER, PROPOSITION_POWER).
*/
function getPowerAtBlock(
address user,
uint256 blockNumber,
DelegationType delegationType
)
external
view
virtual
returns (uint256);
}
// File contracts/governance/token/GovernancePowerDelegationERC20Mixin.sol
pragma solidity 0.7.5;
/**
* @title GovernancePowerDelegationERC20Mixin
* @author dYdX
*
* @dev Provides support for two types of governance powers, both endowed by the governance
* token, and separately delegatable. Provides functions for delegation and for querying a user's
* power at a certain block number.
*/
abstract contract GovernancePowerDelegationERC20Mixin is
ERC20,
IGovernancePowerDelegationERC20
{
using SafeMath for uint256;
// ============ Constants ============
/// @notice EIP-712 typehash for delegation by signature of a specific governance power type.
bytes32 public constant DELEGATE_BY_TYPE_TYPEHASH = keccak256(
'DelegateByType(address delegatee,uint256 type,uint256 nonce,uint256 expiry)'
);
/// @notice EIP-712 typehash for delegation by signature of all governance powers.
bytes32 public constant DELEGATE_TYPEHASH = keccak256(
'Delegate(address delegatee,uint256 nonce,uint256 expiry)'
);
// ============ Structs ============
/// @dev Snapshot of a value on a specific block, used to track voting power for proposals.
struct Snapshot {
uint128 blockNumber;
uint128 value;
}
// ============ External Functions ============
/**
* @notice Delegates a specific governance power to a delegatee.
*
* @param delegatee The address to delegate power to.
* @param delegationType The type of delegation (VOTING_POWER, PROPOSITION_POWER).
*/
function delegateByType(
address delegatee,
DelegationType delegationType
)
external
override
{
_delegateByType(msg.sender, delegatee, delegationType);
}
/**
* @notice Delegates all governance powers to a delegatee.
*
* @param delegatee The address to delegate power to.
*/
function delegate(
address delegatee
)
external
override
{
_delegateByType(msg.sender, delegatee, DelegationType.VOTING_POWER);
_delegateByType(msg.sender, delegatee, DelegationType.PROPOSITION_POWER);
}
/**
* @notice Returns the delegatee of a user.
*
* @param delegator The address of the delegator.
* @param delegationType The type of delegation (VOTING_POWER, PROPOSITION_POWER).
*/
function getDelegateeByType(
address delegator,
DelegationType delegationType
)
external
override
view
returns (address)
{
(, , mapping(address => address) storage delegates) = _getDelegationDataByType(delegationType);
return _getDelegatee(delegator, delegates);
}
/**
* @notice Returns the current power of a user. The current power is the power delegated
* at the time of the last snapshot.
*
* @param user The user whose power to query.
* @param delegationType The type of power (VOTING_POWER, PROPOSITION_POWER).
*/
function getPowerCurrent(
address user,
DelegationType delegationType
)
external
override
view
returns (uint256)
{
(
mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
mapping(address => uint256) storage snapshotsCounts,
// delegates
) = _getDelegationDataByType(delegationType);
return _searchByBlockNumber(snapshots, snapshotsCounts, user, block.number);
}
/**
* @notice Returns the power of a user at a certain block.
*
* @param user The user whose power to query.
* @param blockNumber The block number at which to get the user's power.
* @param delegationType The type of power (VOTING_POWER, PROPOSITION_POWER).
*/
function getPowerAtBlock(
address user,
uint256 blockNumber,
DelegationType delegationType
)
external
override
view
returns (uint256)
{
(
mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
mapping(address => uint256) storage snapshotsCounts,
// delegates
) = _getDelegationDataByType(delegationType);
return _searchByBlockNumber(snapshots, snapshotsCounts, user, blockNumber);
}
// ============ Internal Functions ============
/**
* @dev Delegates one specific power to a delegatee.
*
* @param delegator The user whose power to delegate.
* @param delegatee The address to delegate power to.
* @param delegationType The type of power (VOTING_POWER, PROPOSITION_POWER).
*/
function _delegateByType(
address delegator,
address delegatee,
DelegationType delegationType
)
internal
{
require(
delegatee != address(0),
'INVALID_DELEGATEE'
);
(, , mapping(address => address) storage delegates) = _getDelegationDataByType(delegationType);
uint256 delegatorBalance = balanceOf(delegator);
address previousDelegatee = _getDelegatee(delegator, delegates);
delegates[delegator] = delegatee;
_moveDelegatesByType(previousDelegatee, delegatee, delegatorBalance, delegationType);
emit DelegateChanged(delegator, delegatee, delegationType);
}
/**
* @dev Moves power from one user to another.
*
* @param from The user from which delegated power is moved.
* @param to The user that will receive the delegated power.
* @param amount The amount of power to be moved.
* @param delegationType The type of power (VOTING_POWER, PROPOSITION_POWER).
*/
function _moveDelegatesByType(
address from,
address to,
uint256 amount,
DelegationType delegationType
)
internal
{
if (from == to) {
return;
}
(
mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
mapping(address => uint256) storage snapshotsCounts,
// delegates
) = _getDelegationDataByType(delegationType);
if (from != address(0)) {
uint256 previous = 0;
uint256 fromSnapshotsCount = snapshotsCounts[from];
if (fromSnapshotsCount != 0) {
previous = snapshots[from][fromSnapshotsCount - 1].value;
} else {
previous = balanceOf(from);
}
uint256 newAmount = previous.sub(amount);
_writeSnapshot(
snapshots,
snapshotsCounts,
from,
uint128(newAmount)
);
emit DelegatedPowerChanged(from, newAmount, delegationType);
}
if (to != address(0)) {
uint256 previous = 0;
uint256 toSnapshotsCount = snapshotsCounts[to];
if (toSnapshotsCount != 0) {
previous = snapshots[to][toSnapshotsCount - 1].value;
} else {
previous = balanceOf(to);
}
uint256 newAmount = previous.add(amount);
_writeSnapshot(
snapshots,
snapshotsCounts,
to,
uint128(newAmount)
);
emit DelegatedPowerChanged(to, newAmount, delegationType);
}
}
/**
* @dev Searches for a balance snapshot by block number using binary search.
*
* @param snapshots The mapping of snapshots by user.
* @param snapshotsCounts The mapping of the number of snapshots by user.
* @param user The user for which the snapshot is being searched.
* @param blockNumber The block number being searched.
*/
function _searchByBlockNumber(
mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
mapping(address => uint256) storage snapshotsCounts,
address user,
uint256 blockNumber
)
internal
view
returns (uint256)
{
require(
blockNumber <= block.number,
'INVALID_BLOCK_NUMBER'
);
uint256 snapshotsCount = snapshotsCounts[user];
if (snapshotsCount == 0) {
return balanceOf(user);
}
// First check most recent balance
if (snapshots[user][snapshotsCount - 1].blockNumber <= blockNumber) {
return snapshots[user][snapshotsCount - 1].value;
}
// Next check implicit zero balance
if (snapshots[user][0].blockNumber > blockNumber) {
return 0;
}
uint256 lower = 0;
uint256 upper = snapshotsCount - 1;
while (upper > lower) {
uint256 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
Snapshot memory snapshot = snapshots[user][center];
if (snapshot.blockNumber == blockNumber) {
return snapshot.value;
} else if (snapshot.blockNumber < blockNumber) {
lower = center;
} else {
upper = center - 1;
}
}
return snapshots[user][lower].value;
}
/**
* @dev Returns delegation data (snapshot, snapshotsCount, delegates) by delegation type.
*
* Note: This mixin contract does not itself define any storage, and we require the inheriting
* contract to implement this method to provide access to the relevant mappings in storage.
* This pattern was implemented by Aave for legacy reasons and we have decided not to change it.
*
* @param delegationType The type of power (VOTING_POWER, PROPOSITION_POWER).
*/
function _getDelegationDataByType(
DelegationType delegationType
)
internal
virtual
view
returns (
mapping(address => mapping(uint256 => Snapshot)) storage, // snapshots
mapping(address => uint256) storage, // snapshotsCount
mapping(address => address) storage // delegates
);
/**
* @dev Writes a snapshot of a user's token/power balance.
*
* @param snapshots The mapping of snapshots by user.
* @param snapshotsCounts The mapping of the number of snapshots by user.
* @param owner The user whose power to snapshot.
* @param newValue The new balance to snapshot at the current block.
*/
function _writeSnapshot(
mapping(address => mapping(uint256 => Snapshot)) storage snapshots,
mapping(address => uint256) storage snapshotsCounts,
address owner,
uint128 newValue
)
internal
{
uint128 currentBlock = uint128(block.number);
uint256 ownerSnapshotsCount = snapshotsCounts[owner];
mapping(uint256 => Snapshot) storage ownerSnapshots = snapshots[owner];
if (
ownerSnapshotsCount != 0 &&
ownerSnapshots[ownerSnapshotsCount - 1].blockNumber == currentBlock
) {
// Doing multiple operations in the same block
ownerSnapshots[ownerSnapshotsCount - 1].value = newValue;
} else {
ownerSnapshots[ownerSnapshotsCount] = Snapshot(currentBlock, newValue);
snapshotsCounts[owner] = ownerSnapshotsCount + 1;
}
}
/**
* @dev Returns the delegatee of a user. If a user never performed any delegation, their
* delegated address will be 0x0, in which case we return the user's own address.
*
* @param delegator The address of the user for which return the delegatee.
* @param delegates The mapping of delegates for a particular type of delegation.
*/
function _getDelegatee(
address delegator,
mapping(address => address) storage delegates
)
internal
view
returns (address)
{
address previousDelegatee = delegates[delegator];
if (previousDelegatee == address(0)) {
return delegator;
}
return previousDelegatee;
}
}
// File contracts/governance/token/DydxToken.sol
pragma solidity 0.7.5;
/**
* @title DydxToken
* @author dYdX
*
* @notice The dYdX governance token.
*/
contract DydxToken is
GovernancePowerDelegationERC20Mixin,
Ownable
{
using SafeMath for uint256;
// ============ Events ============
/**
* @dev Emitted when an address has been added to or removed from the token transfer allowlist.
*
* @param account Address that was added to or removed from the token transfer allowlist.
* @param isAllowed True if the address was added to the allowlist, false if removed.
*/
event TransferAllowlistUpdated(
address account,
bool isAllowed
);
/**
* @dev Emitted when the transfer restriction timestamp is reassigned.
*
* @param transfersRestrictedBefore The new timestamp on and after which non-allowlisted
* transfers may occur.
*/
event TransfersRestrictedBeforeUpdated(
uint256 transfersRestrictedBefore
);
// ============ Constants ============
string internal constant NAME = 'dYdX';
string internal constant SYMBOL = 'DYDX';
uint256 public constant INITIAL_SUPPLY = 1_000_000_000 ether;
bytes32 public immutable DOMAIN_SEPARATOR;
bytes public constant EIP712_VERSION = '1';
bytes32 public constant EIP712_DOMAIN = keccak256(
'EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'
);
bytes32 public constant PERMIT_TYPEHASH = keccak256(
'Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)'
);
/// @notice Minimum time between mints.
uint256 public constant MINT_MIN_INTERVAL = 365 days;
/// @notice Cap on the percentage of the total supply that can be minted at each mint.
/// Denominated in percentage points (units out of 100).
uint256 public immutable MINT_MAX_PERCENT;
/// @notice The timestamp on and after which the transfer restriction must be lifted.
uint256 public immutable TRANSFER_RESTRICTION_LIFTED_NO_LATER_THAN;
// ============ Storage ============
/// @dev Mapping from (owner) => (next valid nonce) for EIP-712 signatures.
mapping(address => uint256) internal _nonces;
mapping(address => mapping(uint256 => Snapshot)) public _votingSnapshots;
mapping(address => uint256) public _votingSnapshotsCounts;
mapping(address => address) public _votingDelegates;
mapping(address => mapping(uint256 => Snapshot)) public _propositionPowerSnapshots;
mapping(address => uint256) public _propositionPowerSnapshotsCounts;
mapping(address => address) public _propositionPowerDelegates;
/// @notice Snapshots of the token total supply, at each block where the total supply has changed.
mapping(uint256 => Snapshot) public _totalSupplySnapshots;
/// @notice Number of snapshots of the token total supply.
uint256 public _totalSupplySnapshotsCount;
/// @notice Allowlist of addresses which may send or receive tokens while transfers are
/// otherwise restricted.
mapping(address => bool) public _tokenTransferAllowlist;
/// @notice The timestamp on and after which minting may occur.
uint256 public _mintingRestrictedBefore;
/// @notice The timestamp on and after which non-allowlisted transfers may occur.
uint256 public _transfersRestrictedBefore;
// ============ Constructor ============
/**
* @notice Constructor.
*
* @param distributor The address which will receive the initial supply of tokens.
* @param transfersRestrictedBefore Timestamp, before which transfers are restricted unless the
* origin or destination address is in the allowlist.
* @param transferRestrictionLiftedNoLaterThan Timestamp, which is the maximum timestamp that transfer
* restrictions can be extended to.
* @param mintingRestrictedBefore Timestamp, before which minting is not allowed.
* @param mintMaxPercent Cap on the percentage of the total supply that can be minted at
* each mint.
*/
constructor(
address distributor,
uint256 transfersRestrictedBefore,
uint256 transferRestrictionLiftedNoLaterThan,
uint256 mintingRestrictedBefore,
uint256 mintMaxPercent
)
ERC20(NAME, SYMBOL)
{
uint256 chainId;
// solium-disable-next-line
assembly {
chainId := chainid()
}
DOMAIN_SEPARATOR = keccak256(
abi.encode(
EIP712_DOMAIN,
keccak256(bytes(NAME)),
keccak256(bytes(EIP712_VERSION)),
chainId,
address(this)
)
);
// Validate and set parameters.
require(
transfersRestrictedBefore > block.timestamp,
'TRANSFERS_RESTRICTED_BEFORE_TOO_EARLY'
);
require(
transfersRestrictedBefore <= transferRestrictionLiftedNoLaterThan,
'MAX_TRANSFER_RESTRICTION_TOO_EARLY'
);
require(
mintingRestrictedBefore > block.timestamp,
'MINTING_RESTRICTED_BEFORE_TOO_EARLY'
);
_transfersRestrictedBefore = transfersRestrictedBefore;
TRANSFER_RESTRICTION_LIFTED_NO_LATER_THAN = transferRestrictionLiftedNoLaterThan;
_mintingRestrictedBefore = mintingRestrictedBefore;
MINT_MAX_PERCENT = mintMaxPercent;
// Mint the initial supply.
_mint(distributor, INITIAL_SUPPLY);
emit TransfersRestrictedBeforeUpdated(transfersRestrictedBefore);
}
// ============ Other Functions ============
/**
* @notice Adds addresses to the token transfer allowlist. Reverts if any of the addresses
* already exist in the allowlist. Only callable by owner.
*
* @param addressesToAdd Addresses to add to the token transfer allowlist.
*/
function addToTokenTransferAllowlist(
address[] calldata addressesToAdd
)
external
onlyOwner
{
for (uint256 i = 0; i < addressesToAdd.length; i++) {
require(
!_tokenTransferAllowlist[addressesToAdd[i]],
'ADDRESS_EXISTS_IN_TRANSFER_ALLOWLIST'
);
_tokenTransferAllowlist[addressesToAdd[i]] = true;
emit TransferAllowlistUpdated(addressesToAdd[i], true);
}
}
/**
* @notice Removes addresses from the token transfer allowlist. Reverts if any of the addresses
* don't exist in the allowlist. Only callable by owner.
*
* @param addressesToRemove Addresses to remove from the token transfer allowlist.
*/
function removeFromTokenTransferAllowlist(
address[] calldata addressesToRemove
)
external
onlyOwner
{
for (uint256 i = 0; i < addressesToRemove.length; i++) {
require(
_tokenTransferAllowlist[addressesToRemove[i]],
'ADDRESS_DOES_NOT_EXIST_IN_TRANSFER_ALLOWLIST'
);
_tokenTransferAllowlist[addressesToRemove[i]] = false;
emit TransferAllowlistUpdated(addressesToRemove[i], false);
}
}
/**
* @notice Updates the transfer restriction. Reverts if the transfer restriction has already passed,
* the new transfer restriction is earlier than the previous one, or the new transfer restriction is
* after the maximum transfer restriction.
*
* @param transfersRestrictedBefore The timestamp on and after which non-allowlisted transfers may occur.
*/
function updateTransfersRestrictedBefore(
uint256 transfersRestrictedBefore
)
external
onlyOwner
{
uint256 previousTransfersRestrictedBefore = _transfersRestrictedBefore;
require(
block.timestamp < previousTransfersRestrictedBefore,
'TRANSFER_RESTRICTION_ENDED'
);
require(
previousTransfersRestrictedBefore <= transfersRestrictedBefore,
'NEW_TRANSFER_RESTRICTION_TOO_EARLY'
);
require(
transfersRestrictedBefore <= TRANSFER_RESTRICTION_LIFTED_NO_LATER_THAN,
'AFTER_MAX_TRANSFER_RESTRICTION'
);
_transfersRestrictedBefore = transfersRestrictedBefore;
emit TransfersRestrictedBeforeUpdated(transfersRestrictedBefore);
}
/**
* @notice Mint new tokens. Only callable by owner after the required time period has elapsed.
*
* @param recipient The address to receive minted tokens.
* @param amount The number of tokens to mint.
*/
function mint(
address recipient,
uint256 amount
)
external
onlyOwner
{
require(
block.timestamp >= _mintingRestrictedBefore,
'MINT_TOO_EARLY'
);
require(
amount <= totalSupply().mul(MINT_MAX_PERCENT).div(100),
'MAX_MINT_EXCEEDED'
);
// Update the next allowed minting time.
_mintingRestrictedBefore = block.timestamp.add(MINT_MIN_INTERVAL);
// Mint the amount.
_mint(recipient, amount);
}
/**
* @notice Implements the permit function as specified in EIP-2612.
*
* @param owner Address of the token owner.
* @param spender Address of the spender.
* @param value Amount of allowance.
* @param deadline Expiration timestamp for the signature.
* @param v Signature param.
* @param r Signature param.
* @param s Signature param.
*/
function permit(
address owner,
address spender,
uint256 value,
uint256 deadline,
uint8 v,
bytes32 r,
bytes32 s
)
external
{
require(
owner != address(0),
'INVALID_OWNER'
);
require(
block.timestamp <= deadline,
'INVALID_EXPIRATION'
);
uint256 currentValidNonce = _nonces[owner];
bytes32 digest = keccak256(
abi.encodePacked(
'\x19\x01',
DOMAIN_SEPARATOR,
keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, currentValidNonce, deadline))
)
);
require(
owner == ecrecover(digest, v, r, s),
'INVALID_SIGNATURE'
);
_nonces[owner] = currentValidNonce.add(1);
_approve(owner, spender, value);
}
/**
* @notice Get the next valid nonce for EIP-712 signatures.
*
* This nonce should be used when signing for any of the following functions:
* - permit()
* - delegateByTypeBySig()
* - delegateBySig()
*/
function nonces(
address owner
)
external
view
returns (uint256)
{
return _nonces[owner];
}
function transfer(
address recipient,
uint256 amount
)
public
override
returns (bool)
{
_requireTransferAllowed(_msgSender(), recipient);
return super.transfer(recipient, amount);
}
function transferFrom(
address sender,
address recipient,
uint256 amount
)
public
override
returns (bool)
{
_requireTransferAllowed(sender, recipient);
return super.transferFrom(sender, recipient, amount);
}
/**
* @dev Override _mint() to write a snapshot whenever the total supply changes.
*
* These snapshots are intended to be used by the governance strategy.
*
* Note that the ERC20 _burn() function is never used. If desired, an official burn mechanism
* could be implemented external to this contract, and accounted for in the governance strategy.
*/
function _mint(
address account,
uint256 amount
)
internal
override
{
super._mint(account, amount);
uint256 snapshotsCount = _totalSupplySnapshotsCount;
uint128 currentBlock = uint128(block.number);
uint128 newValue = uint128(totalSupply());
// Note: There is no special case for the total supply being updated multiple times in the same
// block. That should never occur.
_totalSupplySnapshots[snapshotsCount] = Snapshot(currentBlock, newValue);
_totalSupplySnapshotsCount = snapshotsCount.add(1);
}
function _requireTransferAllowed(
address sender,
address recipient
)
view
internal
{
// Compare against the constant `TRANSFER_RESTRICTION_LIFTED_NO_LATER_THAN` first
// to avoid additional gas costs from reading from storage.
if (
block.timestamp < TRANSFER_RESTRICTION_LIFTED_NO_LATER_THAN &&
block.timestamp < _transfersRestrictedBefore
) {
// While transfers are restricted, a transfer is permitted if either the sender or the
// recipient is on the allowlist.
require(
_tokenTransferAllowlist[sender] || _tokenTransferAllowlist[recipient],
'NON_ALLOWLIST_TRANSFERS_DISABLED'
);
}
}
/**
* @dev Writes a snapshot before any transfer operation, including: _transfer, _mint and _burn.
* - On _transfer, it writes snapshots for both 'from' and 'to'.
* - On _mint, only for `to`.
* - On _burn, only for `from`.
*
* @param from The sender.
* @param to The recipient.
* @param amount The amount being transfered.
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
)
internal
override
{
address votingFromDelegatee = _getDelegatee(from, _votingDelegates);
address votingToDelegatee = _getDelegatee(to, _votingDelegates);
_moveDelegatesByType(
votingFromDelegatee,
votingToDelegatee,
amount,
DelegationType.VOTING_POWER
);
address propPowerFromDelegatee = _getDelegatee(from, _propositionPowerDelegates);
address propPowerToDelegatee = _getDelegatee(to, _propositionPowerDelegates);
_moveDelegatesByType(
propPowerFromDelegatee,
propPowerToDelegatee,
amount,
DelegationType.PROPOSITION_POWER
);
}
function _getDelegationDataByType(
DelegationType delegationType
)
internal
override
view
returns (
mapping(address => mapping(uint256 => Snapshot)) storage, // snapshots
mapping(address => uint256) storage, // snapshots count
mapping(address => address) storage // delegatees list
)
{
if (delegationType == DelegationType.VOTING_POWER) {
return (_votingSnapshots, _votingSnapshotsCounts, _votingDelegates);
} else {
return (
_propositionPowerSnapshots,
_propositionPowerSnapshotsCounts,
_propositionPowerDelegates
);
}
}
/**
* @dev Delegates specific governance power from signer to `delegatee` using an EIP-712 signature.
*
* @param delegatee The address to delegate votes to.
* @param delegationType The type of delegation (VOTING_POWER, PROPOSITION_POWER).
* @param nonce The signer's nonce for EIP-712 signatures on this contract.
* @param expiry Expiration timestamp for the signature.
* @param v Signature param.
* @param r Signature param.
* @param s Signature param.
*/
function delegateByTypeBySig(
address delegatee,
DelegationType delegationType,
uint256 nonce,
uint256 expiry,
uint8 v,
bytes32 r,
bytes32 s
)
public
{
bytes32 structHash = keccak256(
abi.encode(DELEGATE_BY_TYPE_TYPEHASH, delegatee, uint256(delegationType), nonce, expiry)
);
bytes32 digest = keccak256(abi.encodePacked('\x19\x01', DOMAIN_SEPARATOR, structHash));
address signer = ecrecover(digest, v, r, s);
require(
signer != address(0),
'INVALID_SIGNATURE'
);
require(
nonce == _nonces[signer]++,
'INVALID_NONCE'
);
require(
block.timestamp <= expiry,
'INVALID_EXPIRATION'
);
_delegateByType(signer, delegatee, delegationType);
}
/**
* @dev Delegates both governance powers from signer to `delegatee` using an EIP-712 signature.
*
* @param delegatee The address to delegate votes to.
* @param nonce The signer's nonce for EIP-712 signatures on this contract.
* @param expiry Expiration timestamp for the signature.
* @param v Signature param.
* @param r Signature param.
* @param s Signature param.
*/
function delegateBySig(
address delegatee,
uint256 nonce,
uint256 expiry,
uint8 v,
bytes32 r,
bytes32 s
)
public
{
bytes32 structHash = keccak256(abi.encode(DELEGATE_TYPEHASH, delegatee, nonce, expiry));
bytes32 digest = keccak256(abi.encodePacked('\x19\x01', DOMAIN_SEPARATOR, structHash));
address signer = ecrecover(digest, v, r, s);
require(
signer != address(0),
'INVALID_SIGNATURE'
);
require(
nonce == _nonces[signer]++,
'INVALID_NONCE'
);
require(
block.timestamp <= expiry,
'INVALID_EXPIRATION'
);
_delegateByType(signer, delegatee, DelegationType.VOTING_POWER);
_delegateByType(signer, delegatee, DelegationType.PROPOSITION_POWER);
}
}