Contract Name:
IlluviumCorePool
Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "./IlluviumPoolBase.sol";
/**
* @title Illuvium Core Pool
*
* @notice Core pools represent permanent pools like ILV or ILV/ETH Pair pool,
* core pools allow staking for arbitrary periods of time up to 1 year
*
* @dev See IlluviumPoolBase for more details
*
* @author Pedro Bergamini, reviewed by Basil Gorin
*/
contract IlluviumCorePool is IlluviumPoolBase {
/// @dev Flag indicating pool type, false means "core pool"
bool public constant override isFlashPool = false;
/// @dev Link to deployed IlluviumVault instance
address public vault;
/// @dev Used to calculate vault rewards
/// @dev This value is different from "reward per token" used in locked pool
/// @dev Note: stakes are different in duration and "weight" reflects that
uint256 public vaultRewardsPerWeight;
/// @dev Pool tokens value available in the pool;
/// pool token examples are ILV (ILV core pool) or ILV/ETH pair (LP core pool)
/// @dev For LP core pool this value doesnt' count for ILV tokens received as Vault rewards
/// while for ILV core pool it does count for such tokens as well
uint256 public poolTokenReserve;
/**
* @dev Fired in receiveVaultRewards()
*
* @param _by an address that sent the rewards, always a vault
* @param amount amount of tokens received
*/
event VaultRewardsReceived(address indexed _by, uint256 amount);
/**
* @dev Fired in _processVaultRewards() and dependent functions, like processRewards()
*
* @param _by an address which executed the function
* @param _to an address which received a reward
* @param amount amount of reward received
*/
event VaultRewardsClaimed(address indexed _by, address indexed _to, uint256 amount);
/**
* @dev Fired in setVault()
*
* @param _by an address which executed the function, always a factory owner
*/
event VaultUpdated(address indexed _by, address _fromVal, address _toVal);
/**
* @dev Creates/deploys an instance of the core pool
*
* @param _ilv ILV ERC20 Token IlluviumERC20 address
* @param _silv sILV ERC20 Token EscrowedIlluviumERC20 address
* @param _factory Pool factory IlluviumPoolFactory instance/address
* @param _poolToken token the pool operates on, for example ILV or ILV/ETH pair
* @param _initBlock initial block used to calculate the rewards
* @param _weight number representing a weight of the pool, actual weight fraction
* is calculated as that number divided by the total pools weight and doesn't exceed one
*/
constructor(
address _ilv,
address _silv,
IlluviumPoolFactory _factory,
address _poolToken,
uint64 _initBlock,
uint32 _weight
) IlluviumPoolBase(_ilv, _silv, _factory, _poolToken, _initBlock, _weight) {}
/**
* @notice Calculates current vault rewards value available for address specified
*
* @dev Performs calculations based on current smart contract state only,
* not taking into account any additional time/blocks which might have passed
*
* @param _staker an address to calculate vault rewards value for
* @return pending calculated vault reward value for the given address
*/
function pendingVaultRewards(address _staker) public view returns (uint256 pending) {
User memory user = users[_staker];
return weightToReward(user.totalWeight, vaultRewardsPerWeight) - user.subVaultRewards;
}
/**
* @dev Executed only by the factory owner to Set the vault
*
* @param _vault an address of deployed IlluviumVault instance
*/
function setVault(address _vault) external {
// verify function is executed by the factory owner
require(factory.owner() == msg.sender, "access denied");
// verify input is set
require(_vault != address(0), "zero input");
// emit an event
emit VaultUpdated(msg.sender, vault, _vault);
// update vault address
vault = _vault;
}
/**
* @dev Executed by the vault to transfer vault rewards ILV from the vault
* into the pool
*
* @dev This function is executed only for ILV core pools
*
* @param _rewardsAmount amount of ILV rewards to transfer into the pool
*/
function receiveVaultRewards(uint256 _rewardsAmount) external {
require(msg.sender == vault, "access denied");
// return silently if there is no reward to receive
if (_rewardsAmount == 0) {
return;
}
require(usersLockingWeight > 0, "zero locking weight");
transferIlvFrom(msg.sender, address(this), _rewardsAmount);
vaultRewardsPerWeight += rewardToWeight(_rewardsAmount, usersLockingWeight);
// update `poolTokenReserve` only if this is a ILV Core Pool
if (poolToken == ilv) {
poolTokenReserve += _rewardsAmount;
}
emit VaultRewardsReceived(msg.sender, _rewardsAmount);
}
/**
* @notice Service function to calculate and pay pending vault and yield rewards to the sender
*
* @dev Internally executes similar function `_processRewards` from the parent smart contract
* to calculate and pay yield rewards; adds vault rewards processing
*
* @dev Can be executed by anyone at any time, but has an effect only when
* executed by deposit holder and when at least one block passes from the
* previous reward processing
* @dev Executed internally when "staking as a pool" (`stakeAsPool`)
* @dev When timing conditions are not met (executed too frequently, or after factory
* end block), function doesn't throw and exits silently
*
* @dev _useSILV flag has a context of yield rewards only
*
* @param _useSILV flag indicating whether to mint sILV token as a reward or not;
* when set to true - sILV reward is minted immediately and sent to sender,
* when set to false - new ILV reward deposit gets created if pool is an ILV pool
* (poolToken is ILV token), or new pool deposit gets created together with sILV minted
* when pool is not an ILV pool (poolToken is not an ILV token)
*/
function processRewards(bool _useSILV) external override {
_processRewards(msg.sender, _useSILV, true);
}
/**
* @dev Executed internally by the pool itself (from the parent `IlluviumPoolBase` smart contract)
* as part of yield rewards processing logic (`IlluviumPoolBase._processRewards` function)
* @dev Executed when _useSILV is false and pool is not an ILV pool - see `IlluviumPoolBase._processRewards`
*
* @param _staker an address which stakes (the yield reward)
* @param _amount amount to be staked (yield reward amount)
*/
function stakeAsPool(address _staker, uint256 _amount) external {
require(factory.poolExists(msg.sender), "access denied");
_sync();
User storage user = users[_staker];
if (user.tokenAmount > 0) {
_processRewards(_staker, true, false);
}
uint256 depositWeight = _amount * YEAR_STAKE_WEIGHT_MULTIPLIER;
Deposit memory newDeposit =
Deposit({
tokenAmount: _amount,
lockedFrom: uint64(now256()),
lockedUntil: uint64(now256() + 365 days),
weight: depositWeight,
isYield: true
});
user.tokenAmount += _amount;
user.totalWeight += depositWeight;
user.deposits.push(newDeposit);
usersLockingWeight += depositWeight;
user.subYieldRewards = weightToReward(user.totalWeight, yieldRewardsPerWeight);
user.subVaultRewards = weightToReward(user.totalWeight, vaultRewardsPerWeight);
// update `poolTokenReserve` only if this is a LP Core Pool (stakeAsPool can be executed only for LP pool)
poolTokenReserve += _amount;
}
/**
* @inheritdoc IlluviumPoolBase
*
* @dev Additionally to the parent smart contract, updates vault rewards of the holder,
* and updates (increases) pool token reserve (pool tokens value available in the pool)
*/
function _stake(
address _staker,
uint256 _amount,
uint64 _lockedUntil,
bool _useSILV,
bool _isYield
) internal override {
super._stake(_staker, _amount, _lockedUntil, _useSILV, _isYield);
User storage user = users[_staker];
user.subVaultRewards = weightToReward(user.totalWeight, vaultRewardsPerWeight);
poolTokenReserve += _amount;
}
/**
* @inheritdoc IlluviumPoolBase
*
* @dev Additionally to the parent smart contract, updates vault rewards of the holder,
* and updates (decreases) pool token reserve (pool tokens value available in the pool)
*/
function _unstake(
address _staker,
uint256 _depositId,
uint256 _amount,
bool _useSILV
) internal override {
User storage user = users[_staker];
Deposit memory stakeDeposit = user.deposits[_depositId];
require(stakeDeposit.lockedFrom == 0 || now256() > stakeDeposit.lockedUntil, "deposit not yet unlocked");
poolTokenReserve -= _amount;
super._unstake(_staker, _depositId, _amount, _useSILV);
user.subVaultRewards = weightToReward(user.totalWeight, vaultRewardsPerWeight);
}
/**
* @inheritdoc IlluviumPoolBase
*
* @dev Additionally to the parent smart contract, processes vault rewards of the holder,
* and for ILV pool updates (increases) pool token reserve (pool tokens value available in the pool)
*/
function _processRewards(
address _staker,
bool _useSILV,
bool _withUpdate
) internal override returns (uint256 pendingYield) {
_processVaultRewards(_staker);
pendingYield = super._processRewards(_staker, _useSILV, _withUpdate);
// update `poolTokenReserve` only if this is a ILV Core Pool
if (poolToken == ilv && !_useSILV) {
poolTokenReserve += pendingYield;
}
}
/**
* @dev Used internally to process vault rewards for the staker
*
* @param _staker address of the user (staker) to process rewards for
*/
function _processVaultRewards(address _staker) private {
User storage user = users[_staker];
uint256 pendingVaultClaim = pendingVaultRewards(_staker);
if (pendingVaultClaim == 0) return;
// read ILV token balance of the pool via standard ERC20 interface
uint256 ilvBalance = IERC20(ilv).balanceOf(address(this));
require(ilvBalance >= pendingVaultClaim, "contract ILV balance too low");
// update `poolTokenReserve` only if this is a ILV Core Pool
if (poolToken == ilv) {
// protects against rounding errors
poolTokenReserve -= pendingVaultClaim > poolTokenReserve ? poolTokenReserve : pendingVaultClaim;
}
user.subVaultRewards = weightToReward(user.totalWeight, vaultRewardsPerWeight);
// transfer fails if pool ILV balance is not enough - which is a desired behavior
transferIlv(_staker, pendingVaultClaim);
emit VaultRewardsClaimed(msg.sender, _staker, pendingVaultClaim);
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "../interfaces/IPool.sol";
import "../interfaces/ICorePool.sol";
import "./ReentrancyGuard.sol";
import "./IlluviumPoolFactory.sol";
import "../utils/SafeERC20.sol";
import "../token/EscrowedIlluviumERC20.sol";
/**
* @title Illuvium Pool Base
*
* @notice An abstract contract containing common logic for any pool,
* be it a flash pool (temporary pool like SNX) or a core pool (permanent pool like ILV/ETH or ILV pool)
*
* @dev Deployment and initialization.
* Any pool deployed must be bound to the deployed pool factory (IlluviumPoolFactory)
* Additionally, 3 token instance addresses must be defined on deployment:
* - ILV token address
* - sILV token address, used to mint sILV rewards
* - pool token address, it can be ILV token address, ILV/ETH pair address, and others
*
* @dev Pool weight defines the fraction of the yield current pool receives among the other pools,
* pool factory is responsible for the weight synchronization between the pools.
* @dev The weight is logically 10% for ILV pool and 90% for ILV/ETH pool.
* Since Solidity doesn't support fractions the weight is defined by the division of
* pool weight by total pools weight (sum of all registered pools within the factory)
* @dev For ILV Pool we use 100 as weight and for ILV/ETH pool - 900.
*
* @author Pedro Bergamini, reviewed by Basil Gorin
*/
abstract contract IlluviumPoolBase is IPool, IlluviumAware, ReentrancyGuard {
/// @dev Data structure representing token holder using a pool
struct User {
// @dev Total staked amount
uint256 tokenAmount;
// @dev Total weight
uint256 totalWeight;
// @dev Auxiliary variable for yield calculation
uint256 subYieldRewards;
// @dev Auxiliary variable for vault rewards calculation
uint256 subVaultRewards;
// @dev An array of holder's deposits
Deposit[] deposits;
}
/// @dev Token holder storage, maps token holder address to their data record
mapping(address => User) public users;
/// @dev Link to sILV ERC20 Token EscrowedIlluviumERC20 instance
address public immutable override silv;
/// @dev Link to the pool factory IlluviumPoolFactory instance
IlluviumPoolFactory public immutable factory;
/// @dev Link to the pool token instance, for example ILV or ILV/ETH pair
address public immutable override poolToken;
/// @dev Pool weight, 100 for ILV pool or 900 for ILV/ETH
uint32 public override weight;
/// @dev Block number of the last yield distribution event
uint64 public override lastYieldDistribution;
/// @dev Used to calculate yield rewards
/// @dev This value is different from "reward per token" used in locked pool
/// @dev Note: stakes are different in duration and "weight" reflects that
uint256 public override yieldRewardsPerWeight;
/// @dev Used to calculate yield rewards, keeps track of the tokens weight locked in staking
uint256 public override usersLockingWeight;
/**
* @dev Stake weight is proportional to deposit amount and time locked, precisely
* "deposit amount wei multiplied by (fraction of the year locked plus one)"
* @dev To avoid significant precision loss due to multiplication by "fraction of the year" [0, 1],
* weight is stored multiplied by 1e6 constant, as an integer
* @dev Corner case 1: if time locked is zero, weight is deposit amount multiplied by 1e6
* @dev Corner case 2: if time locked is one year, fraction of the year locked is one, and
* weight is a deposit amount multiplied by 2 * 1e6
*/
uint256 internal constant WEIGHT_MULTIPLIER = 1e6;
/**
* @dev When we know beforehand that staking is done for a year, and fraction of the year locked is one,
* we use simplified calculation and use the following constant instead previos one
*/
uint256 internal constant YEAR_STAKE_WEIGHT_MULTIPLIER = 2 * WEIGHT_MULTIPLIER;
/**
* @dev Rewards per weight are stored multiplied by 1e12, as integers.
*/
uint256 internal constant REWARD_PER_WEIGHT_MULTIPLIER = 1e12;
/**
* @dev Fired in _stake() and stake()
*
* @param _by an address which performed an operation, usually token holder
* @param _from token holder address, the tokens will be returned to that address
* @param amount amount of tokens staked
*/
event Staked(address indexed _by, address indexed _from, uint256 amount);
/**
* @dev Fired in _updateStakeLock() and updateStakeLock()
*
* @param _by an address which performed an operation
* @param depositId updated deposit ID
* @param lockedFrom deposit locked from value
* @param lockedUntil updated deposit locked until value
*/
event StakeLockUpdated(address indexed _by, uint256 depositId, uint64 lockedFrom, uint64 lockedUntil);
/**
* @dev Fired in _unstake() and unstake()
*
* @param _by an address which performed an operation, usually token holder
* @param _to an address which received the unstaked tokens, usually token holder
* @param amount amount of tokens unstaked
*/
event Unstaked(address indexed _by, address indexed _to, uint256 amount);
/**
* @dev Fired in _sync(), sync() and dependent functions (stake, unstake, etc.)
*
* @param _by an address which performed an operation
* @param yieldRewardsPerWeight updated yield rewards per weight value
* @param lastYieldDistribution usually, current block number
*/
event Synchronized(address indexed _by, uint256 yieldRewardsPerWeight, uint64 lastYieldDistribution);
/**
* @dev Fired in _processRewards(), processRewards() and dependent functions (stake, unstake, etc.)
*
* @param _by an address which performed an operation
* @param _to an address which claimed the yield reward
* @param sIlv flag indicating if reward was paid (minted) in sILV
* @param amount amount of yield paid
*/
event YieldClaimed(address indexed _by, address indexed _to, bool sIlv, uint256 amount);
/**
* @dev Fired in setWeight()
*
* @param _by an address which performed an operation, always a factory
* @param _fromVal old pool weight value
* @param _toVal new pool weight value
*/
event PoolWeightUpdated(address indexed _by, uint32 _fromVal, uint32 _toVal);
/**
* @dev Overridden in sub-contracts to construct the pool
*
* @param _ilv ILV ERC20 Token IlluviumERC20 address
* @param _silv sILV ERC20 Token EscrowedIlluviumERC20 address
* @param _factory Pool factory IlluviumPoolFactory instance/address
* @param _poolToken token the pool operates on, for example ILV or ILV/ETH pair
* @param _initBlock initial block used to calculate the rewards
* note: _initBlock can be set to the future effectively meaning _sync() calls will do nothing
* @param _weight number representing a weight of the pool, actual weight fraction
* is calculated as that number divided by the total pools weight and doesn't exceed one
*/
constructor(
address _ilv,
address _silv,
IlluviumPoolFactory _factory,
address _poolToken,
uint64 _initBlock,
uint32 _weight
) IlluviumAware(_ilv) {
// verify the inputs are set
require(_silv != address(0), "sILV address not set");
require(address(_factory) != address(0), "ILV Pool fct address not set");
require(_poolToken != address(0), "pool token address not set");
require(_initBlock > 0, "init block not set");
require(_weight > 0, "pool weight not set");
// verify sILV instance supplied
require(
EscrowedIlluviumERC20(_silv).TOKEN_UID() ==
0xac3051b8d4f50966afb632468a4f61483ae6a953b74e387a01ef94316d6b7d62,
"unexpected sILV TOKEN_UID"
);
// verify IlluviumPoolFactory instance supplied
require(
_factory.FACTORY_UID() == 0xc5cfd88c6e4d7e5c8a03c255f03af23c0918d8e82cac196f57466af3fd4a5ec7,
"unexpected FACTORY_UID"
);
// save the inputs into internal state variables
silv = _silv;
factory = _factory;
poolToken = _poolToken;
weight = _weight;
// init the dependent internal state variables
lastYieldDistribution = _initBlock;
}
/**
* @notice Calculates current yield rewards value available for address specified
*
* @param _staker an address to calculate yield rewards value for
* @return calculated yield reward value for the given address
*/
function pendingYieldRewards(address _staker) external view override returns (uint256) {
// `newYieldRewardsPerWeight` will store stored or recalculated value for `yieldRewardsPerWeight`
uint256 newYieldRewardsPerWeight;
// if smart contract state was not updated recently, `yieldRewardsPerWeight` value
// is outdated and we need to recalculate it in order to calculate pending rewards correctly
if (blockNumber() > lastYieldDistribution && usersLockingWeight != 0) {
uint256 endBlock = factory.endBlock();
uint256 multiplier =
blockNumber() > endBlock ? endBlock - lastYieldDistribution : blockNumber() - lastYieldDistribution;
uint256 ilvRewards = (multiplier * weight * factory.ilvPerBlock()) / factory.totalWeight();
// recalculated value for `yieldRewardsPerWeight`
newYieldRewardsPerWeight = rewardToWeight(ilvRewards, usersLockingWeight) + yieldRewardsPerWeight;
} else {
// if smart contract state is up to date, we don't recalculate
newYieldRewardsPerWeight = yieldRewardsPerWeight;
}
// based on the rewards per weight value, calculate pending rewards;
User memory user = users[_staker];
uint256 pending = weightToReward(user.totalWeight, newYieldRewardsPerWeight) - user.subYieldRewards;
return pending;
}
/**
* @notice Returns total staked token balance for the given address
*
* @param _user an address to query balance for
* @return total staked token balance
*/
function balanceOf(address _user) external view override returns (uint256) {
// read specified user token amount and return
return users[_user].tokenAmount;
}
/**
* @notice Returns information on the given deposit for the given address
*
* @dev See getDepositsLength
*
* @param _user an address to query deposit for
* @param _depositId zero-indexed deposit ID for the address specified
* @return deposit info as Deposit structure
*/
function getDeposit(address _user, uint256 _depositId) external view override returns (Deposit memory) {
// read deposit at specified index and return
return users[_user].deposits[_depositId];
}
/**
* @notice Returns number of deposits for the given address. Allows iteration over deposits.
*
* @dev See getDeposit
*
* @param _user an address to query deposit length for
* @return number of deposits for the given address
*/
function getDepositsLength(address _user) external view override returns (uint256) {
// read deposits array length and return
return users[_user].deposits.length;
}
/**
* @notice Stakes specified amount of tokens for the specified amount of time,
* and pays pending yield rewards if any
*
* @dev Requires amount to stake to be greater than zero
*
* @param _amount amount of tokens to stake
* @param _lockUntil stake period as unix timestamp; zero means no locking
* @param _useSILV a flag indicating if previous reward to be paid as sILV
*/
function stake(
uint256 _amount,
uint64 _lockUntil,
bool _useSILV
) external override {
// delegate call to an internal function
_stake(msg.sender, _amount, _lockUntil, _useSILV, false);
}
/**
* @notice Unstakes specified amount of tokens, and pays pending yield rewards if any
*
* @dev Requires amount to unstake to be greater than zero
*
* @param _depositId deposit ID to unstake from, zero-indexed
* @param _amount amount of tokens to unstake
* @param _useSILV a flag indicating if reward to be paid as sILV
*/
function unstake(
uint256 _depositId,
uint256 _amount,
bool _useSILV
) external override {
// delegate call to an internal function
_unstake(msg.sender, _depositId, _amount, _useSILV);
}
/**
* @notice Extends locking period for a given deposit
*
* @dev Requires new lockedUntil value to be:
* higher than the current one, and
* in the future, but
* no more than 1 year in the future
*
* @param depositId updated deposit ID
* @param lockedUntil updated deposit locked until value
* @param useSILV used for _processRewards check if it should use ILV or sILV
*/
function updateStakeLock(
uint256 depositId,
uint64 lockedUntil,
bool useSILV
) external {
// sync and call processRewards
_sync();
_processRewards(msg.sender, useSILV, false);
// delegate call to an internal function
_updateStakeLock(msg.sender, depositId, lockedUntil);
}
/**
* @notice Service function to synchronize pool state with current time
*
* @dev Can be executed by anyone at any time, but has an effect only when
* at least one block passes between synchronizations
* @dev Executed internally when staking, unstaking, processing rewards in order
* for calculations to be correct and to reflect state progress of the contract
* @dev When timing conditions are not met (executed too frequently, or after factory
* end block), function doesn't throw and exits silently
*/
function sync() external override {
// delegate call to an internal function
_sync();
}
/**
* @notice Service function to calculate and pay pending yield rewards to the sender
*
* @dev Can be executed by anyone at any time, but has an effect only when
* executed by deposit holder and when at least one block passes from the
* previous reward processing
* @dev Executed internally when staking and unstaking, executes sync() under the hood
* before making further calculations and payouts
* @dev When timing conditions are not met (executed too frequently, or after factory
* end block), function doesn't throw and exits silently
*
* @param _useSILV flag indicating whether to mint sILV token as a reward or not;
* when set to true - sILV reward is minted immediately and sent to sender,
* when set to false - new ILV reward deposit gets created if pool is an ILV pool
* (poolToken is ILV token), or new pool deposit gets created together with sILV minted
* when pool is not an ILV pool (poolToken is not an ILV token)
*/
function processRewards(bool _useSILV) external virtual override {
// delegate call to an internal function
_processRewards(msg.sender, _useSILV, true);
}
/**
* @dev Executed by the factory to modify pool weight; the factory is expected
* to keep track of the total pools weight when updating
*
* @dev Set weight to zero to disable the pool
*
* @param _weight new weight to set for the pool
*/
function setWeight(uint32 _weight) external override {
// verify function is executed by the factory
require(msg.sender == address(factory), "access denied");
// emit an event logging old and new weight values
emit PoolWeightUpdated(msg.sender, weight, _weight);
// set the new weight value
weight = _weight;
}
/**
* @dev Similar to public pendingYieldRewards, but performs calculations based on
* current smart contract state only, not taking into account any additional
* time/blocks which might have passed
*
* @param _staker an address to calculate yield rewards value for
* @return pending calculated yield reward value for the given address
*/
function _pendingYieldRewards(address _staker) internal view returns (uint256 pending) {
// read user data structure into memory
User memory user = users[_staker];
// and perform the calculation using the values read
return weightToReward(user.totalWeight, yieldRewardsPerWeight) - user.subYieldRewards;
}
/**
* @dev Used internally, mostly by children implementations, see stake()
*
* @param _staker an address which stakes tokens and which will receive them back
* @param _amount amount of tokens to stake
* @param _lockUntil stake period as unix timestamp; zero means no locking
* @param _useSILV a flag indicating if previous reward to be paid as sILV
* @param _isYield a flag indicating if that stake is created to store yield reward
* from the previously unstaked stake
*/
function _stake(
address _staker,
uint256 _amount,
uint64 _lockUntil,
bool _useSILV,
bool _isYield
) internal virtual {
// validate the inputs
require(_amount > 0, "zero amount");
require(
_lockUntil == 0 || (_lockUntil > now256() && _lockUntil - now256() <= 365 days),
"invalid lock interval"
);
// update smart contract state
_sync();
// get a link to user data struct, we will write to it later
User storage user = users[_staker];
// process current pending rewards if any
if (user.tokenAmount > 0) {
_processRewards(_staker, _useSILV, false);
}
// in most of the cases added amount `addedAmount` is simply `_amount`
// however for deflationary tokens this can be different
// read the current balance
uint256 previousBalance = IERC20(poolToken).balanceOf(address(this));
// transfer `_amount`; note: some tokens may get burnt here
transferPoolTokenFrom(address(msg.sender), address(this), _amount);
// read new balance, usually this is just the difference `previousBalance - _amount`
uint256 newBalance = IERC20(poolToken).balanceOf(address(this));
// calculate real amount taking into account deflation
uint256 addedAmount = newBalance - previousBalance;
// set the `lockFrom` and `lockUntil` taking into account that
// zero value for `_lockUntil` means "no locking" and leads to zero values
// for both `lockFrom` and `lockUntil`
uint64 lockFrom = _lockUntil > 0 ? uint64(now256()) : 0;
uint64 lockUntil = _lockUntil;
// stake weight formula rewards for locking
uint256 stakeWeight =
(((lockUntil - lockFrom) * WEIGHT_MULTIPLIER) / 365 days + WEIGHT_MULTIPLIER) * addedAmount;
// makes sure stakeWeight is valid
assert(stakeWeight > 0);
// create and save the deposit (append it to deposits array)
Deposit memory deposit =
Deposit({
tokenAmount: addedAmount,
weight: stakeWeight,
lockedFrom: lockFrom,
lockedUntil: lockUntil,
isYield: _isYield
});
// deposit ID is an index of the deposit in `deposits` array
user.deposits.push(deposit);
// update user record
user.tokenAmount += addedAmount;
user.totalWeight += stakeWeight;
user.subYieldRewards = weightToReward(user.totalWeight, yieldRewardsPerWeight);
// update global variable
usersLockingWeight += stakeWeight;
// emit an event
emit Staked(msg.sender, _staker, _amount);
}
/**
* @dev Used internally, mostly by children implementations, see unstake()
*
* @param _staker an address which unstakes tokens (which previously staked them)
* @param _depositId deposit ID to unstake from, zero-indexed
* @param _amount amount of tokens to unstake
* @param _useSILV a flag indicating if reward to be paid as sILV
*/
function _unstake(
address _staker,
uint256 _depositId,
uint256 _amount,
bool _useSILV
) internal virtual {
// verify an amount is set
require(_amount > 0, "zero amount");
// get a link to user data struct, we will write to it later
User storage user = users[_staker];
// get a link to the corresponding deposit, we may write to it later
Deposit storage stakeDeposit = user.deposits[_depositId];
// deposit structure may get deleted, so we save isYield flag to be able to use it
bool isYield = stakeDeposit.isYield;
// verify available balance
// if staker address ot deposit doesn't exist this check will fail as well
require(stakeDeposit.tokenAmount >= _amount, "amount exceeds stake");
// update smart contract state
_sync();
// and process current pending rewards if any
_processRewards(_staker, _useSILV, false);
// recalculate deposit weight
uint256 previousWeight = stakeDeposit.weight;
uint256 newWeight =
(((stakeDeposit.lockedUntil - stakeDeposit.lockedFrom) * WEIGHT_MULTIPLIER) /
365 days +
WEIGHT_MULTIPLIER) * (stakeDeposit.tokenAmount - _amount);
// update the deposit, or delete it if its depleted
if (stakeDeposit.tokenAmount - _amount == 0) {
delete user.deposits[_depositId];
} else {
stakeDeposit.tokenAmount -= _amount;
stakeDeposit.weight = newWeight;
}
// update user record
user.tokenAmount -= _amount;
user.totalWeight = user.totalWeight - previousWeight + newWeight;
user.subYieldRewards = weightToReward(user.totalWeight, yieldRewardsPerWeight);
// update global variable
usersLockingWeight = usersLockingWeight - previousWeight + newWeight;
// if the deposit was created by the pool itself as a yield reward
if (isYield) {
// mint the yield via the factory
factory.mintYieldTo(msg.sender, _amount);
} else {
// otherwise just return tokens back to holder
transferPoolToken(msg.sender, _amount);
}
// emit an event
emit Unstaked(msg.sender, _staker, _amount);
}
/**
* @dev Used internally, mostly by children implementations, see sync()
*
* @dev Updates smart contract state (`yieldRewardsPerWeight`, `lastYieldDistribution`),
* updates factory state via `updateILVPerBlock`
*/
function _sync() internal virtual {
// update ILV per block value in factory if required
if (factory.shouldUpdateRatio()) {
factory.updateILVPerBlock();
}
// check bound conditions and if these are not met -
// exit silently, without emitting an event
uint256 endBlock = factory.endBlock();
if (lastYieldDistribution >= endBlock) {
return;
}
if (blockNumber() <= lastYieldDistribution) {
return;
}
// if locking weight is zero - update only `lastYieldDistribution` and exit
if (usersLockingWeight == 0) {
lastYieldDistribution = uint64(blockNumber());
return;
}
// to calculate the reward we need to know how many blocks passed, and reward per block
uint256 currentBlock = blockNumber() > endBlock ? endBlock : blockNumber();
uint256 blocksPassed = currentBlock - lastYieldDistribution;
uint256 ilvPerBlock = factory.ilvPerBlock();
// calculate the reward
uint256 ilvReward = (blocksPassed * ilvPerBlock * weight) / factory.totalWeight();
// update rewards per weight and `lastYieldDistribution`
yieldRewardsPerWeight += rewardToWeight(ilvReward, usersLockingWeight);
lastYieldDistribution = uint64(currentBlock);
// emit an event
emit Synchronized(msg.sender, yieldRewardsPerWeight, lastYieldDistribution);
}
/**
* @dev Used internally, mostly by children implementations, see processRewards()
*
* @param _staker an address which receives the reward (which has staked some tokens earlier)
* @param _useSILV flag indicating whether to mint sILV token as a reward or not, see processRewards()
* @param _withUpdate flag allowing to disable synchronization (see sync()) if set to false
* @return pendingYield the rewards calculated and optionally re-staked
*/
function _processRewards(
address _staker,
bool _useSILV,
bool _withUpdate
) internal virtual returns (uint256 pendingYield) {
// update smart contract state if required
if (_withUpdate) {
_sync();
}
// calculate pending yield rewards, this value will be returned
pendingYield = _pendingYieldRewards(_staker);
// if pending yield is zero - just return silently
if (pendingYield == 0) return 0;
// get link to a user data structure, we will write into it later
User storage user = users[_staker];
// if sILV is requested
if (_useSILV) {
// - mint sILV
mintSIlv(_staker, pendingYield);
} else if (poolToken == ilv) {
// calculate pending yield weight,
// 2e6 is the bonus weight when staking for 1 year
uint256 depositWeight = pendingYield * YEAR_STAKE_WEIGHT_MULTIPLIER;
// if the pool is ILV Pool - create new ILV deposit
// and save it - push it into deposits array
Deposit memory newDeposit =
Deposit({
tokenAmount: pendingYield,
lockedFrom: uint64(now256()),
lockedUntil: uint64(now256() + 365 days), // staking yield for 1 year
weight: depositWeight,
isYield: true
});
user.deposits.push(newDeposit);
// update user record
user.tokenAmount += pendingYield;
user.totalWeight += depositWeight;
// update global variable
usersLockingWeight += depositWeight;
} else {
// for other pools - stake as pool
address ilvPool = factory.getPoolAddress(ilv);
ICorePool(ilvPool).stakeAsPool(_staker, pendingYield);
}
// update users's record for `subYieldRewards` if requested
if (_withUpdate) {
user.subYieldRewards = weightToReward(user.totalWeight, yieldRewardsPerWeight);
}
// emit an event
emit YieldClaimed(msg.sender, _staker, _useSILV, pendingYield);
}
/**
* @dev See updateStakeLock()
*
* @param _staker an address to update stake lock
* @param _depositId updated deposit ID
* @param _lockedUntil updated deposit locked until value
*/
function _updateStakeLock(
address _staker,
uint256 _depositId,
uint64 _lockedUntil
) internal {
// validate the input time
require(_lockedUntil > now256(), "lock should be in the future");
// get a link to user data struct, we will write to it later
User storage user = users[_staker];
// get a link to the corresponding deposit, we may write to it later
Deposit storage stakeDeposit = user.deposits[_depositId];
// validate the input against deposit structure
require(_lockedUntil > stakeDeposit.lockedUntil, "invalid new lock");
// verify locked from and locked until values
if (stakeDeposit.lockedFrom == 0) {
require(_lockedUntil - now256() <= 365 days, "max lock period is 365 days");
stakeDeposit.lockedFrom = uint64(now256());
} else {
require(_lockedUntil - stakeDeposit.lockedFrom <= 365 days, "max lock period is 365 days");
}
// update locked until value, calculate new weight
stakeDeposit.lockedUntil = _lockedUntil;
uint256 newWeight =
(((stakeDeposit.lockedUntil - stakeDeposit.lockedFrom) * WEIGHT_MULTIPLIER) /
365 days +
WEIGHT_MULTIPLIER) * stakeDeposit.tokenAmount;
// save previous weight
uint256 previousWeight = stakeDeposit.weight;
// update weight
stakeDeposit.weight = newWeight;
// update user total weight and global locking weight
user.totalWeight = user.totalWeight - previousWeight + newWeight;
usersLockingWeight = usersLockingWeight - previousWeight + newWeight;
// emit an event
emit StakeLockUpdated(_staker, _depositId, stakeDeposit.lockedFrom, _lockedUntil);
}
/**
* @dev Converts stake weight (not to be mixed with the pool weight) to
* ILV reward value, applying the 10^12 division on weight
*
* @param _weight stake weight
* @param rewardPerWeight ILV reward per weight
* @return reward value normalized to 10^12
*/
function weightToReward(uint256 _weight, uint256 rewardPerWeight) public pure returns (uint256) {
// apply the formula and return
return (_weight * rewardPerWeight) / REWARD_PER_WEIGHT_MULTIPLIER;
}
/**
* @dev Converts reward ILV value to stake weight (not to be mixed with the pool weight),
* applying the 10^12 multiplication on the reward
* - OR -
* @dev Converts reward ILV value to reward/weight if stake weight is supplied as second
* function parameter instead of reward/weight
*
* @param reward yield reward
* @param rewardPerWeight reward/weight (or stake weight)
* @return stake weight (or reward/weight)
*/
function rewardToWeight(uint256 reward, uint256 rewardPerWeight) public pure returns (uint256) {
// apply the reverse formula and return
return (reward * REWARD_PER_WEIGHT_MULTIPLIER) / rewardPerWeight;
}
/**
* @dev Testing time-dependent functionality is difficult and the best way of
* doing it is to override block number in helper test smart contracts
*
* @return `block.number` in mainnet, custom values in testnets (if overridden)
*/
function blockNumber() public view virtual returns (uint256) {
// return current block number
return block.number;
}
/**
* @dev Testing time-dependent functionality is difficult and the best way of
* doing it is to override time in helper test smart contracts
*
* @return `block.timestamp` in mainnet, custom values in testnets (if overridden)
*/
function now256() public view virtual returns (uint256) {
// return current block timestamp
return block.timestamp;
}
/**
* @dev Executes EscrowedIlluviumERC20.mint(_to, _values)
* on the bound EscrowedIlluviumERC20 instance
*
* @dev Reentrancy safe due to the EscrowedIlluviumERC20 design
*/
function mintSIlv(address _to, uint256 _value) private {
// just delegate call to the target
EscrowedIlluviumERC20(silv).mint(_to, _value);
}
/**
* @dev Executes SafeERC20.safeTransfer on a pool token
*
* @dev Reentrancy safety enforced via `ReentrancyGuard.nonReentrant`
*/
function transferPoolToken(address _to, uint256 _value) internal nonReentrant {
// just delegate call to the target
SafeERC20.safeTransfer(IERC20(poolToken), _to, _value);
}
/**
* @dev Executes SafeERC20.safeTransferFrom on a pool token
*
* @dev Reentrancy safety enforced via `ReentrancyGuard.nonReentrant`
*/
function transferPoolTokenFrom(
address _from,
address _to,
uint256 _value
) internal nonReentrant {
// just delegate call to the target
SafeERC20.safeTransferFrom(IERC20(poolToken), _from, _to, _value);
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "./ILinkedToILV.sol";
/**
* @title Illuvium Pool
*
* @notice An abstraction representing a pool, see IlluviumPoolBase for details
*
* @author Pedro Bergamini, reviewed by Basil Gorin
*/
interface IPool is ILinkedToILV {
/**
* @dev Deposit is a key data structure used in staking,
* it represents a unit of stake with its amount, weight and term (time interval)
*/
struct Deposit {
// @dev token amount staked
uint256 tokenAmount;
// @dev stake weight
uint256 weight;
// @dev locking period - from
uint64 lockedFrom;
// @dev locking period - until
uint64 lockedUntil;
// @dev indicates if the stake was created as a yield reward
bool isYield;
}
// for the rest of the functions see Soldoc in IlluviumPoolBase
function silv() external view returns (address);
function poolToken() external view returns (address);
function isFlashPool() external view returns (bool);
function weight() external view returns (uint32);
function lastYieldDistribution() external view returns (uint64);
function yieldRewardsPerWeight() external view returns (uint256);
function usersLockingWeight() external view returns (uint256);
function pendingYieldRewards(address _user) external view returns (uint256);
function balanceOf(address _user) external view returns (uint256);
function getDeposit(address _user, uint256 _depositId) external view returns (Deposit memory);
function getDepositsLength(address _user) external view returns (uint256);
function stake(
uint256 _amount,
uint64 _lockedUntil,
bool useSILV
) external;
function unstake(
uint256 _depositId,
uint256 _amount,
bool useSILV
) external;
function sync() external;
function processRewards(bool useSILV) external;
function setWeight(uint32 _weight) external;
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "./IPool.sol";
interface ICorePool is IPool {
function vaultRewardsPerToken() external view returns (uint256);
function poolTokenReserve() external view returns (uint256);
function stakeAsPool(address _staker, uint256 _amount) external;
function receiveVaultRewards(uint256 _amount) external;
}
// https://raw.githubusercontent.com/OpenZeppelin/openzeppelin-contracts/master/contracts/security/ReentrancyGuard.sol
// #24a0bc23cfe3fbc76f8f2510b78af1e948ae6651
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
/**
* @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].
*/
abstract 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 () {
_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;
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "../interfaces/IPool.sol";
import "./IlluviumAware.sol";
import "./IlluviumCorePool.sol";
import "../token/EscrowedIlluviumERC20.sol";
import "../utils/Ownable.sol";
/**
* @title Illuvium Pool Factory
*
* @notice ILV Pool Factory manages Illuvium Yield farming pools, provides a single
* public interface to access the pools, provides an interface for the pools
* to mint yield rewards, access pool-related info, update weights, etc.
*
* @notice The factory is authorized (via its owner) to register new pools, change weights
* of the existing pools, removing the pools (by changing their weights to zero)
*
* @dev The factory requires ROLE_TOKEN_CREATOR permission on the ILV token to mint yield
* (see `mintYieldTo` function)
*
* @author Pedro Bergamini, reviewed by Basil Gorin
*/
contract IlluviumPoolFactory is Ownable, IlluviumAware {
/**
* @dev Smart contract unique identifier, a random number
* @dev Should be regenerated each time smart contact source code is changed
* and changes smart contract itself is to be redeployed
* @dev Generated using https://www.random.org/bytes/
*/
uint256 public constant FACTORY_UID = 0xc5cfd88c6e4d7e5c8a03c255f03af23c0918d8e82cac196f57466af3fd4a5ec7;
/// @dev Auxiliary data structure used only in getPoolData() view function
struct PoolData {
// @dev pool token address (like ILV)
address poolToken;
// @dev pool address (like deployed core pool instance)
address poolAddress;
// @dev pool weight (200 for ILV pools, 800 for ILV/ETH pools - set during deployment)
uint32 weight;
// @dev flash pool flag
bool isFlashPool;
}
/**
* @dev ILV/block determines yield farming reward base
* used by the yield pools controlled by the factory
*/
uint192 public ilvPerBlock;
/**
* @dev The yield is distributed proportionally to pool weights;
* total weight is here to help in determining the proportion
*/
uint32 public totalWeight;
/**
* @dev ILV/block decreases by 3% every blocks/update (set to 91252 blocks during deployment);
* an update is triggered by executing `updateILVPerBlock` public function
*/
uint32 public immutable blocksPerUpdate;
/**
* @dev End block is the last block when ILV/block can be decreased;
* it is implied that yield farming stops after that block
*/
uint32 public endBlock;
/**
* @dev Each time the ILV/block ratio gets updated, the block number
* when the operation has occurred gets recorded into `lastRatioUpdate`
* @dev This block number is then used to check if blocks/update `blocksPerUpdate`
* has passed when decreasing yield reward by 3%
*/
uint32 public lastRatioUpdate;
/// @dev sILV token address is used to create ILV core pool(s)
address public immutable silv;
/// @dev Maps pool token address (like ILV) -> pool address (like core pool instance)
mapping(address => address) public pools;
/// @dev Keeps track of registered pool addresses, maps pool address -> exists flag
mapping(address => bool) public poolExists;
/**
* @dev Fired in createPool() and registerPool()
*
* @param _by an address which executed an action
* @param poolToken pool token address (like ILV)
* @param poolAddress deployed pool instance address
* @param weight pool weight
* @param isFlashPool flag indicating if pool is a flash pool
*/
event PoolRegistered(
address indexed _by,
address indexed poolToken,
address indexed poolAddress,
uint64 weight,
bool isFlashPool
);
/**
* @dev Fired in changePoolWeight()
*
* @param _by an address which executed an action
* @param poolAddress deployed pool instance address
* @param weight new pool weight
*/
event WeightUpdated(address indexed _by, address indexed poolAddress, uint32 weight);
/**
* @dev Fired in updateILVPerBlock()
*
* @param _by an address which executed an action
* @param newIlvPerBlock new ILV/block value
*/
event IlvRatioUpdated(address indexed _by, uint256 newIlvPerBlock);
/**
* @dev Creates/deploys a factory instance
*
* @param _ilv ILV ERC20 token address
* @param _silv sILV ERC20 token address
* @param _ilvPerBlock initial ILV/block value for rewards
* @param _blocksPerUpdate how frequently the rewards gets updated (decreased by 3%), blocks
* @param _initBlock block number to measure _blocksPerUpdate from
* @param _endBlock block number when farming stops and rewards cannot be updated anymore
*/
constructor(
address _ilv,
address _silv,
uint192 _ilvPerBlock,
uint32 _blocksPerUpdate,
uint32 _initBlock,
uint32 _endBlock
) IlluviumAware(_ilv) {
// verify the inputs are set
require(_silv != address(0), "sILV address not set");
require(_ilvPerBlock > 0, "ILV/block not set");
require(_blocksPerUpdate > 0, "blocks/update not set");
require(_initBlock > 0, "init block not set");
require(_endBlock > _initBlock, "invalid end block: must be greater than init block");
// verify sILV instance supplied
require(
EscrowedIlluviumERC20(_silv).TOKEN_UID() ==
0xac3051b8d4f50966afb632468a4f61483ae6a953b74e387a01ef94316d6b7d62,
"unexpected sILV TOKEN_UID"
);
// save the inputs into internal state variables
silv = _silv;
ilvPerBlock = _ilvPerBlock;
blocksPerUpdate = _blocksPerUpdate;
lastRatioUpdate = _initBlock;
endBlock = _endBlock;
}
/**
* @notice Given a pool token retrieves corresponding pool address
*
* @dev A shortcut for `pools` mapping
*
* @param poolToken pool token address (like ILV) to query pool address for
* @return pool address for the token specified
*/
function getPoolAddress(address poolToken) external view returns (address) {
// read the mapping and return
return pools[poolToken];
}
/**
* @notice Reads pool information for the pool defined by its pool token address,
* designed to simplify integration with the front ends
*
* @param _poolToken pool token address to query pool information for
* @return pool information packed in a PoolData struct
*/
function getPoolData(address _poolToken) public view returns (PoolData memory) {
// get the pool address from the mapping
address poolAddr = pools[_poolToken];
// throw if there is no pool registered for the token specified
require(poolAddr != address(0), "pool not found");
// read pool information from the pool smart contract
// via the pool interface (IPool)
address poolToken = IPool(poolAddr).poolToken();
bool isFlashPool = IPool(poolAddr).isFlashPool();
uint32 weight = IPool(poolAddr).weight();
// create the in-memory structure and return it
return PoolData({ poolToken: poolToken, poolAddress: poolAddr, weight: weight, isFlashPool: isFlashPool });
}
/**
* @dev Verifies if `blocksPerUpdate` has passed since last ILV/block
* ratio update and if ILV/block reward can be decreased by 3%
*
* @return true if enough time has passed and `updateILVPerBlock` can be executed
*/
function shouldUpdateRatio() public view returns (bool) {
// if yield farming period has ended
if (blockNumber() > endBlock) {
// ILV/block reward cannot be updated anymore
return false;
}
// check if blocks/update (91252 blocks) have passed since last update
return blockNumber() >= lastRatioUpdate + blocksPerUpdate;
}
/**
* @dev Creates a core pool (IlluviumCorePool) and registers it within the factory
*
* @dev Can be executed by the pool factory owner only
*
* @param poolToken pool token address (like ILV, or ILV/ETH pair)
* @param initBlock init block to be used for the pool created
* @param weight weight of the pool to be created
*/
function createPool(
address poolToken,
uint64 initBlock,
uint32 weight
) external virtual onlyOwner {
// create/deploy new core pool instance
IPool pool = new IlluviumCorePool(ilv, silv, this, poolToken, initBlock, weight);
// register it within a factory
registerPool(address(pool));
}
/**
* @dev Registers an already deployed pool instance within the factory
*
* @dev Can be executed by the pool factory owner only
*
* @param poolAddr address of the already deployed pool instance
*/
function registerPool(address poolAddr) public onlyOwner {
// read pool information from the pool smart contract
// via the pool interface (IPool)
address poolToken = IPool(poolAddr).poolToken();
bool isFlashPool = IPool(poolAddr).isFlashPool();
uint32 weight = IPool(poolAddr).weight();
// ensure that the pool is not already registered within the factory
require(pools[poolToken] == address(0), "this pool is already registered");
// create pool structure, register it within the factory
pools[poolToken] = poolAddr;
poolExists[poolAddr] = true;
// update total pool weight of the factory
totalWeight += weight;
// emit an event
emit PoolRegistered(msg.sender, poolToken, poolAddr, weight, isFlashPool);
}
/**
* @notice Decreases ILV/block reward by 3%, can be executed
* no more than once per `blocksPerUpdate` blocks
*/
function updateILVPerBlock() external {
// checks if ratio can be updated i.e. if blocks/update (91252 blocks) have passed
require(shouldUpdateRatio(), "too frequent");
// decreases ILV/block reward by 3%
ilvPerBlock = (ilvPerBlock * 97) / 100;
// set current block as the last ratio update block
lastRatioUpdate = uint32(blockNumber());
// emit an event
emit IlvRatioUpdated(msg.sender, ilvPerBlock);
}
/**
* @dev Mints ILV tokens; executed by ILV Pool only
*
* @dev Requires factory to have ROLE_TOKEN_CREATOR permission
* on the ILV ERC20 token instance
*
* @param _to an address to mint tokens to
* @param _amount amount of ILV tokens to mint
*/
function mintYieldTo(address _to, uint256 _amount) external {
// verify that sender is a pool registered withing the factory
require(poolExists[msg.sender], "access denied");
// mint ILV tokens as required
mintIlv(_to, _amount);
}
/**
* @dev Changes the weight of the pool;
* executed by the pool itself or by the factory owner
*
* @param poolAddr address of the pool to change weight for
* @param weight new weight value to set to
*/
function changePoolWeight(address poolAddr, uint32 weight) external {
// verify function is executed either by factory owner or by the pool itself
require(msg.sender == owner() || poolExists[msg.sender]);
// recalculate total weight
totalWeight = totalWeight + weight - IPool(poolAddr).weight();
// set the new pool weight
IPool(poolAddr).setWeight(weight);
// emit an event
emit WeightUpdated(msg.sender, poolAddr, weight);
}
/**
* @dev Testing time-dependent functionality is difficult and the best way of
* doing it is to override block number in helper test smart contracts
*
* @return `block.number` in mainnet, custom values in testnets (if overridden)
*/
function blockNumber() public view virtual returns (uint256) {
// return current block number
return block.number;
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "../interfaces/IERC20.sol";
import "./Address.sol";
/**
* @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 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) + 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) - value;
_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");
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "../utils/ERC20.sol";
import "../utils/AccessControl.sol";
contract EscrowedIlluviumERC20 is ERC20("Escrowed Illuvium", "sILV"), AccessControl {
/**
* @dev Smart contract unique identifier, a random number
* @dev Should be regenerated each time smart contact source code is changed
* and changes smart contract itself is to be redeployed
* @dev Generated using https://www.random.org/bytes/
*/
uint256 public constant TOKEN_UID = 0xac3051b8d4f50966afb632468a4f61483ae6a953b74e387a01ef94316d6b7d62;
/**
* @notice Must be called by ROLE_TOKEN_CREATOR addresses.
*
* @param recipient address to receive the tokens.
* @param amount number of tokens to be minted.
*/
function mint(address recipient, uint256 amount) external {
require(isSenderInRole(ROLE_TOKEN_CREATOR), "insufficient privileges (ROLE_TOKEN_CREATOR required)");
_mint(recipient, amount);
}
/**
* @param amount number of tokens to be burned.
*/
function burn(uint256 amount) external {
_burn(msg.sender, amount);
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
/**
* @title Linked to ILV Marker Interface
*
* @notice Marks smart contracts which are linked to IlluviumERC20 token instance upon construction,
* all these smart contracts share a common ilv() address getter
*
* @notice Implementing smart contracts MUST verify that they get linked to real IlluviumERC20 instance
* and that ilv() getter returns this very same instance address
*
* @author Basil Gorin
*/
interface ILinkedToILV {
/**
* @notice Getter for a verified IlluviumERC20 instance address
*
* @return IlluviumERC20 token instance address smart contract is linked to
*/
function ilv() external view returns (address);
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "../token/IlluviumERC20.sol";
import "../interfaces/ILinkedToILV.sol";
/**
* @title Illuvium Aware
*
* @notice Helper smart contract to be inherited by other smart contracts requiring to
* be linked to verified IlluviumERC20 instance and performing some basic tasks on it
*
* @author Basil Gorin
*/
abstract contract IlluviumAware is ILinkedToILV {
/// @dev Link to ILV ERC20 Token IlluviumERC20 instance
address public immutable override ilv;
/**
* @dev Creates IlluviumAware instance, requiring to supply deployed IlluviumERC20 instance address
*
* @param _ilv deployed IlluviumERC20 instance address
*/
constructor(address _ilv) {
// verify ILV address is set and is correct
require(_ilv != address(0), "ILV address not set");
require(IlluviumERC20(_ilv).TOKEN_UID() == 0x83ecb176af7c4f35a45ff0018282e3a05a1018065da866182df12285866f5a2c, "unexpected TOKEN_UID");
// write ILV address
ilv = _ilv;
}
/**
* @dev Executes IlluviumERC20.safeTransferFrom(address(this), _to, _value, "")
* on the bound IlluviumERC20 instance
*
* @dev Reentrancy safe due to the IlluviumERC20 design
*/
function transferIlv(address _to, uint256 _value) internal {
// just delegate call to the target
transferIlvFrom(address(this), _to, _value);
}
/**
* @dev Executes IlluviumERC20.transferFrom(_from, _to, _value)
* on the bound IlluviumERC20 instance
*
* @dev Reentrancy safe due to the IlluviumERC20 design
*/
function transferIlvFrom(address _from, address _to, uint256 _value) internal {
// just delegate call to the target
IlluviumERC20(ilv).transferFrom(_from, _to, _value);
}
/**
* @dev Executes IlluviumERC20.mint(_to, _values)
* on the bound IlluviumERC20 instance
*
* @dev Reentrancy safe due to the IlluviumERC20 design
*/
function mintIlv(address _to, uint256 _value) internal {
// just delegate call to the target
IlluviumERC20(ilv).mint(_to, _value);
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
/**
* @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.
*/
abstract contract Ownable {
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 = msg.sender;
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == msg.sender, "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;
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "../utils/AddressUtils.sol";
import "../utils/AccessControl.sol";
import "./ERC20Receiver.sol";
/**
* @title Illuvium (ILV) ERC20 token
*
* @notice Illuvium is a core ERC20 token powering the game.
* It serves as an in-game currency, is tradable on exchanges,
* it powers up the governance protocol (Illuvium DAO) and participates in Yield Farming.
*
* @dev Token Summary:
* - Symbol: ILV
* - Name: Illuvium
* - Decimals: 18
* - Initial token supply: 7,000,000 ILV
* - Maximum final token supply: 10,000,000 ILV
* - Up to 3,000,000 ILV may get minted in 3 years period via yield farming
* - Mintable: total supply may increase
* - Burnable: total supply may decrease
*
* @dev Token balances and total supply are effectively 192 bits long, meaning that maximum
* possible total supply smart contract is able to track is 2^192 (close to 10^40 tokens)
*
* @dev Smart contract doesn't use safe math. All arithmetic operations are overflow/underflow safe.
* Additionally, Solidity 0.8.1 enforces overflow/underflow safety.
*
* @dev ERC20: reviewed according to https://eips.ethereum.org/EIPS/eip-20
*
* @dev ERC20: contract has passed OpenZeppelin ERC20 tests,
* see https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/test/token/ERC20/ERC20.behavior.js
* see https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/test/token/ERC20/ERC20.test.js
* see adopted copies of these tests in the `test` folder
*
* @dev ERC223/ERC777: not supported;
* send tokens via `safeTransferFrom` and implement `ERC20Receiver.onERC20Received` on the receiver instead
*
* @dev Multiple Withdrawal Attack on ERC20 Tokens (ISBN:978-1-7281-3027-9) - resolved
* Related events and functions are marked with "ISBN:978-1-7281-3027-9" tag:
* - event Transferred(address indexed _by, address indexed _from, address indexed _to, uint256 _value)
* - event Approved(address indexed _owner, address indexed _spender, uint256 _oldValue, uint256 _value)
* - function increaseAllowance(address _spender, uint256 _value) public returns (bool)
* - function decreaseAllowance(address _spender, uint256 _value) public returns (bool)
* See: https://ieeexplore.ieee.org/document/8802438
* See: https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* @author Basil Gorin
*/
contract IlluviumERC20 is AccessControl {
/**
* @dev Smart contract unique identifier, a random number
* @dev Should be regenerated each time smart contact source code is changed
* and changes smart contract itself is to be redeployed
* @dev Generated using https://www.random.org/bytes/
*/
uint256 public constant TOKEN_UID = 0x83ecb176af7c4f35a45ff0018282e3a05a1018065da866182df12285866f5a2c;
/**
* @notice Name of the token: Illuvium
*
* @notice ERC20 name of the token (long name)
*
* @dev ERC20 `function name() public view returns (string)`
*
* @dev Field is declared public: getter name() is created when compiled,
* it returns the name of the token.
*/
string public constant name = "Illuvium";
/**
* @notice Symbol of the token: ILV
*
* @notice ERC20 symbol of that token (short name)
*
* @dev ERC20 `function symbol() public view returns (string)`
*
* @dev Field is declared public: getter symbol() is created when compiled,
* it returns the symbol of the token
*/
string public constant symbol = "ILV";
/**
* @notice Decimals of the token: 18
*
* @dev ERC20 `function decimals() public view returns (uint8)`
*
* @dev Field is declared public: getter decimals() is created when compiled,
* it returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `6`, a balance of `1,500,000` tokens should
* be displayed to a user as `1,5` (`1,500,000 / 10 ** 6`).
*
* @dev NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including balanceOf() and transfer().
*/
uint8 public constant decimals = 18;
/**
* @notice Total supply of the token: initially 7,000,000,
* with the potential to grow up to 10,000,000 during yield farming period (3 years)
*
* @dev ERC20 `function totalSupply() public view returns (uint256)`
*
* @dev Field is declared public: getter totalSupply() is created when compiled,
* it returns the amount of tokens in existence.
*/
uint256 public totalSupply; // is set to 7 million * 10^18 in the constructor
/**
* @dev A record of all the token balances
* @dev This mapping keeps record of all token owners:
* owner => balance
*/
mapping(address => uint256) public tokenBalances;
/**
* @notice A record of each account's voting delegate
*
* @dev Auxiliary data structure used to sum up an account's voting power
*
* @dev This mapping keeps record of all voting power delegations:
* voting delegator (token owner) => voting delegate
*/
mapping(address => address) public votingDelegates;
/**
* @notice A voting power record binds voting power of a delegate to a particular
* block when the voting power delegation change happened
*/
struct VotingPowerRecord {
/*
* @dev block.number when delegation has changed; starting from
* that block voting power value is in effect
*/
uint64 blockNumber;
/*
* @dev cumulative voting power a delegate has obtained starting
* from the block stored in blockNumber
*/
uint192 votingPower;
}
/**
* @notice A record of each account's voting power
*
* @dev Primarily data structure to store voting power for each account.
* Voting power sums up from the account's token balance and delegated
* balances.
*
* @dev Stores current value and entire history of its changes.
* The changes are stored as an array of checkpoints.
* Checkpoint is an auxiliary data structure containing voting
* power (number of votes) and block number when the checkpoint is saved
*
* @dev Maps voting delegate => voting power record
*/
mapping(address => VotingPowerRecord[]) public votingPowerHistory;
/**
* @dev A record of nonces for signing/validating signatures in `delegateWithSig`
* for every delegate, increases after successful validation
*
* @dev Maps delegate address => delegate nonce
*/
mapping(address => uint256) public nonces;
/**
* @notice A record of all the allowances to spend tokens on behalf
* @dev Maps token owner address to an address approved to spend
* some tokens on behalf, maps approved address to that amount
* @dev owner => spender => value
*/
mapping(address => mapping(address => uint256)) public transferAllowances;
/**
* @notice Enables ERC20 transfers of the tokens
* (transfer by the token owner himself)
* @dev Feature FEATURE_TRANSFERS must be enabled in order for
* `transfer()` function to succeed
*/
uint32 public constant FEATURE_TRANSFERS = 0x0000_0001;
/**
* @notice Enables ERC20 transfers on behalf
* (transfer by someone else on behalf of token owner)
* @dev Feature FEATURE_TRANSFERS_ON_BEHALF must be enabled in order for
* `transferFrom()` function to succeed
* @dev Token owner must call `approve()` first to authorize
* the transfer on behalf
*/
uint32 public constant FEATURE_TRANSFERS_ON_BEHALF = 0x0000_0002;
/**
* @dev Defines if the default behavior of `transfer` and `transferFrom`
* checks if the receiver smart contract supports ERC20 tokens
* @dev When feature FEATURE_UNSAFE_TRANSFERS is enabled the transfers do not
* check if the receiver smart contract supports ERC20 tokens,
* i.e. `transfer` and `transferFrom` behave like `unsafeTransferFrom`
* @dev When feature FEATURE_UNSAFE_TRANSFERS is disabled (default) the transfers
* check if the receiver smart contract supports ERC20 tokens,
* i.e. `transfer` and `transferFrom` behave like `safeTransferFrom`
*/
uint32 public constant FEATURE_UNSAFE_TRANSFERS = 0x0000_0004;
/**
* @notice Enables token owners to burn their own tokens,
* including locked tokens which are burnt first
* @dev Feature FEATURE_OWN_BURNS must be enabled in order for
* `burn()` function to succeed when called by token owner
*/
uint32 public constant FEATURE_OWN_BURNS = 0x0000_0008;
/**
* @notice Enables approved operators to burn tokens on behalf of their owners,
* including locked tokens which are burnt first
* @dev Feature FEATURE_OWN_BURNS must be enabled in order for
* `burn()` function to succeed when called by approved operator
*/
uint32 public constant FEATURE_BURNS_ON_BEHALF = 0x0000_0010;
/**
* @notice Enables delegators to elect delegates
* @dev Feature FEATURE_DELEGATIONS must be enabled in order for
* `delegate()` function to succeed
*/
uint32 public constant FEATURE_DELEGATIONS = 0x0000_0020;
/**
* @notice Enables delegators to elect delegates on behalf
* (via an EIP712 signature)
* @dev Feature FEATURE_DELEGATIONS must be enabled in order for
* `delegateWithSig()` function to succeed
*/
uint32 public constant FEATURE_DELEGATIONS_ON_BEHALF = 0x0000_0040;
/**
* @notice Token creator is responsible for creating (minting)
* tokens to an arbitrary address
* @dev Role ROLE_TOKEN_CREATOR allows minting tokens
* (calling `mint` function)
*/
uint32 public constant ROLE_TOKEN_CREATOR = 0x0001_0000;
/**
* @notice Token destroyer is responsible for destroying (burning)
* tokens owned by an arbitrary address
* @dev Role ROLE_TOKEN_DESTROYER allows burning tokens
* (calling `burn` function)
*/
uint32 public constant ROLE_TOKEN_DESTROYER = 0x0002_0000;
/**
* @notice ERC20 receivers are allowed to receive tokens without ERC20 safety checks,
* which may be useful to simplify tokens transfers into "legacy" smart contracts
* @dev When `FEATURE_UNSAFE_TRANSFERS` is not enabled addresses having
* `ROLE_ERC20_RECEIVER` permission are allowed to receive tokens
* via `transfer` and `transferFrom` functions in the same way they
* would via `unsafeTransferFrom` function
* @dev When `FEATURE_UNSAFE_TRANSFERS` is enabled `ROLE_ERC20_RECEIVER` permission
* doesn't affect the transfer behaviour since
* `transfer` and `transferFrom` behave like `unsafeTransferFrom` for any receiver
* @dev ROLE_ERC20_RECEIVER is a shortening for ROLE_UNSAFE_ERC20_RECEIVER
*/
uint32 public constant ROLE_ERC20_RECEIVER = 0x0004_0000;
/**
* @notice ERC20 senders are allowed to send tokens without ERC20 safety checks,
* which may be useful to simplify tokens transfers into "legacy" smart contracts
* @dev When `FEATURE_UNSAFE_TRANSFERS` is not enabled senders having
* `ROLE_ERC20_SENDER` permission are allowed to send tokens
* via `transfer` and `transferFrom` functions in the same way they
* would via `unsafeTransferFrom` function
* @dev When `FEATURE_UNSAFE_TRANSFERS` is enabled `ROLE_ERC20_SENDER` permission
* doesn't affect the transfer behaviour since
* `transfer` and `transferFrom` behave like `unsafeTransferFrom` for any receiver
* @dev ROLE_ERC20_SENDER is a shortening for ROLE_UNSAFE_ERC20_SENDER
*/
uint32 public constant ROLE_ERC20_SENDER = 0x0008_0000;
/**
* @dev Magic value to be returned by ERC20Receiver upon successful reception of token(s)
* @dev Equal to `bytes4(keccak256("onERC20Received(address,address,uint256,bytes)"))`,
* which can be also obtained as `ERC20Receiver(address(0)).onERC20Received.selector`
*/
bytes4 private constant ERC20_RECEIVED = 0x4fc35859;
/**
* @notice EIP-712 contract's domain typeHash, see https://eips.ethereum.org/EIPS/eip-712#rationale-for-typehash
*/
bytes32 public constant DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");
/**
* @notice EIP-712 delegation struct typeHash, see https://eips.ethereum.org/EIPS/eip-712#rationale-for-typehash
*/
bytes32 public constant DELEGATION_TYPEHASH = keccak256("Delegation(address delegate,uint256 nonce,uint256 expiry)");
/**
* @dev Fired in transfer(), transferFrom() and some other (non-ERC20) functions
*
* @dev ERC20 `event Transfer(address indexed _from, address indexed _to, uint256 _value)`
*
* @param _from an address tokens were consumed from
* @param _to an address tokens were sent to
* @param _value number of tokens transferred
*/
event Transfer(address indexed _from, address indexed _to, uint256 _value);
/**
* @dev Fired in approve() and approveAtomic() functions
*
* @dev ERC20 `event Approval(address indexed _owner, address indexed _spender, uint256 _value)`
*
* @param _owner an address which granted a permission to transfer
* tokens on its behalf
* @param _spender an address which received a permission to transfer
* tokens on behalf of the owner `_owner`
* @param _value amount of tokens granted to transfer on behalf
*/
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
/**
* @dev Fired in mint() function
*
* @param _by an address which minted some tokens (transaction sender)
* @param _to an address the tokens were minted to
* @param _value an amount of tokens minted
*/
event Minted(address indexed _by, address indexed _to, uint256 _value);
/**
* @dev Fired in burn() function
*
* @param _by an address which burned some tokens (transaction sender)
* @param _from an address the tokens were burnt from
* @param _value an amount of tokens burnt
*/
event Burnt(address indexed _by, address indexed _from, uint256 _value);
/**
* @dev Resolution for the Multiple Withdrawal Attack on ERC20 Tokens (ISBN:978-1-7281-3027-9)
*
* @dev Similar to ERC20 Transfer event, but also logs an address which executed transfer
*
* @dev Fired in transfer(), transferFrom() and some other (non-ERC20) functions
*
* @param _by an address which performed the transfer
* @param _from an address tokens were consumed from
* @param _to an address tokens were sent to
* @param _value number of tokens transferred
*/
event Transferred(address indexed _by, address indexed _from, address indexed _to, uint256 _value);
/**
* @dev Resolution for the Multiple Withdrawal Attack on ERC20 Tokens (ISBN:978-1-7281-3027-9)
*
* @dev Similar to ERC20 Approve event, but also logs old approval value
*
* @dev Fired in approve() and approveAtomic() functions
*
* @param _owner an address which granted a permission to transfer
* tokens on its behalf
* @param _spender an address which received a permission to transfer
* tokens on behalf of the owner `_owner`
* @param _oldValue previously granted amount of tokens to transfer on behalf
* @param _value new granted amount of tokens to transfer on behalf
*/
event Approved(address indexed _owner, address indexed _spender, uint256 _oldValue, uint256 _value);
/**
* @dev Notifies that a key-value pair in `votingDelegates` mapping has changed,
* i.e. a delegator address has changed its delegate address
*
* @param _of delegator address, a token owner
* @param _from old delegate, an address which delegate right is revoked
* @param _to new delegate, an address which received the voting power
*/
event DelegateChanged(address indexed _of, address indexed _from, address indexed _to);
/**
* @dev Notifies that a key-value pair in `votingPowerHistory` mapping has changed,
* i.e. a delegate's voting power has changed.
*
* @param _of delegate whose voting power has changed
* @param _fromVal previous number of votes delegate had
* @param _toVal new number of votes delegate has
*/
event VotingPowerChanged(address indexed _of, uint256 _fromVal, uint256 _toVal);
/**
* @dev Deploys the token smart contract,
* assigns initial token supply to the address specified
*
* @param _initialHolder owner of the initial token supply
*/
constructor(address _initialHolder) {
// verify initial holder address non-zero (is set)
require(_initialHolder != address(0), "_initialHolder not set (zero address)");
// mint initial supply
mint(_initialHolder, 7_000_000e18);
}
// ===== Start: ERC20/ERC223/ERC777 functions =====
/**
* @notice Gets the balance of a particular address
*
* @dev ERC20 `function balanceOf(address _owner) public view returns (uint256 balance)`
*
* @param _owner the address to query the the balance for
* @return balance an amount of tokens owned by the address specified
*/
function balanceOf(address _owner) public view returns (uint256 balance) {
// read the balance and return
return tokenBalances[_owner];
}
/**
* @notice Transfers some tokens to an external address or a smart contract
*
* @dev ERC20 `function transfer(address _to, uint256 _value) public returns (bool success)`
*
* @dev Called by token owner (an address which has a
* positive token balance tracked by this smart contract)
* @dev Throws on any error like
* * insufficient token balance or
* * incorrect `_to` address:
* * zero address or
* * self address or
* * smart contract which doesn't support ERC20
*
* @param _to an address to transfer tokens to,
* must be either an external address or a smart contract,
* compliant with the ERC20 standard
* @param _value amount of tokens to be transferred, must
* be greater than zero
* @return success true on success, throws otherwise
*/
function transfer(address _to, uint256 _value) public returns (bool success) {
// just delegate call to `transferFrom`,
// `FEATURE_TRANSFERS` is verified inside it
return transferFrom(msg.sender, _to, _value);
}
/**
* @notice Transfers some tokens on behalf of address `_from' (token owner)
* to some other address `_to`
*
* @dev ERC20 `function transferFrom(address _from, address _to, uint256 _value) public returns (bool success)`
*
* @dev Called by token owner on his own or approved address,
* an address approved earlier by token owner to
* transfer some amount of tokens on its behalf
* @dev Throws on any error like
* * insufficient token balance or
* * incorrect `_to` address:
* * zero address or
* * same as `_from` address (self transfer)
* * smart contract which doesn't support ERC20
*
* @param _from token owner which approved caller (transaction sender)
* to transfer `_value` of tokens on its behalf
* @param _to an address to transfer tokens to,
* must be either an external address or a smart contract,
* compliant with the ERC20 standard
* @param _value amount of tokens to be transferred, must
* be greater than zero
* @return success true on success, throws otherwise
*/
function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
// depending on `FEATURE_UNSAFE_TRANSFERS` we execute either safe (default)
// or unsafe transfer
// if `FEATURE_UNSAFE_TRANSFERS` is enabled
// or receiver has `ROLE_ERC20_RECEIVER` permission
// or sender has `ROLE_ERC20_SENDER` permission
if(isFeatureEnabled(FEATURE_UNSAFE_TRANSFERS)
|| isOperatorInRole(_to, ROLE_ERC20_RECEIVER)
|| isSenderInRole(ROLE_ERC20_SENDER)) {
// we execute unsafe transfer - delegate call to `unsafeTransferFrom`,
// `FEATURE_TRANSFERS` is verified inside it
unsafeTransferFrom(_from, _to, _value);
}
// otherwise - if `FEATURE_UNSAFE_TRANSFERS` is disabled
// and receiver doesn't have `ROLE_ERC20_RECEIVER` permission
else {
// we execute safe transfer - delegate call to `safeTransferFrom`, passing empty `_data`,
// `FEATURE_TRANSFERS` is verified inside it
safeTransferFrom(_from, _to, _value, "");
}
// both `unsafeTransferFrom` and `safeTransferFrom` throw on any error, so
// if we're here - it means operation successful,
// just return true
return true;
}
/**
* @notice Transfers some tokens on behalf of address `_from' (token owner)
* to some other address `_to`
*
* @dev Inspired by ERC721 safeTransferFrom, this function allows to
* send arbitrary data to the receiver on successful token transfer
* @dev Called by token owner on his own or approved address,
* an address approved earlier by token owner to
* transfer some amount of tokens on its behalf
* @dev Throws on any error like
* * insufficient token balance or
* * incorrect `_to` address:
* * zero address or
* * same as `_from` address (self transfer)
* * smart contract which doesn't support ERC20Receiver interface
* @dev Returns silently on success, throws otherwise
*
* @param _from token owner which approved caller (transaction sender)
* to transfer `_value` of tokens on its behalf
* @param _to an address to transfer tokens to,
* must be either an external address or a smart contract,
* compliant with the ERC20 standard
* @param _value amount of tokens to be transferred, must
* be greater than zero
* @param _data [optional] additional data with no specified format,
* sent in onERC20Received call to `_to` in case if its a smart contract
*/
function safeTransferFrom(address _from, address _to, uint256 _value, bytes memory _data) public {
// first delegate call to `unsafeTransferFrom`
// to perform the unsafe token(s) transfer
unsafeTransferFrom(_from, _to, _value);
// after the successful transfer - check if receiver supports
// ERC20Receiver and execute a callback handler `onERC20Received`,
// reverting whole transaction on any error:
// check if receiver `_to` supports ERC20Receiver interface
if(AddressUtils.isContract(_to)) {
// if `_to` is a contract - execute onERC20Received
bytes4 response = ERC20Receiver(_to).onERC20Received(msg.sender, _from, _value, _data);
// expected response is ERC20_RECEIVED
require(response == ERC20_RECEIVED, "invalid onERC20Received response");
}
}
/**
* @notice Transfers some tokens on behalf of address `_from' (token owner)
* to some other address `_to`
*
* @dev In contrast to `safeTransferFrom` doesn't check recipient
* smart contract to support ERC20 tokens (ERC20Receiver)
* @dev Designed to be used by developers when the receiver is known
* to support ERC20 tokens but doesn't implement ERC20Receiver interface
* @dev Called by token owner on his own or approved address,
* an address approved earlier by token owner to
* transfer some amount of tokens on its behalf
* @dev Throws on any error like
* * insufficient token balance or
* * incorrect `_to` address:
* * zero address or
* * same as `_from` address (self transfer)
* @dev Returns silently on success, throws otherwise
*
* @param _from token owner which approved caller (transaction sender)
* to transfer `_value` of tokens on its behalf
* @param _to an address to transfer tokens to,
* must be either an external address or a smart contract,
* compliant with the ERC20 standard
* @param _value amount of tokens to be transferred, must
* be greater than zero
*/
function unsafeTransferFrom(address _from, address _to, uint256 _value) public {
// if `_from` is equal to sender, require transfers feature to be enabled
// otherwise require transfers on behalf feature to be enabled
require(_from == msg.sender && isFeatureEnabled(FEATURE_TRANSFERS)
|| _from != msg.sender && isFeatureEnabled(FEATURE_TRANSFERS_ON_BEHALF),
_from == msg.sender? "transfers are disabled": "transfers on behalf are disabled");
// non-zero source address check - Zeppelin
// obviously, zero source address is a client mistake
// it's not part of ERC20 standard but it's reasonable to fail fast
// since for zero value transfer transaction succeeds otherwise
require(_from != address(0), "ERC20: transfer from the zero address"); // Zeppelin msg
// non-zero recipient address check
require(_to != address(0), "ERC20: transfer to the zero address"); // Zeppelin msg
// sender and recipient cannot be the same
require(_from != _to, "sender and recipient are the same (_from = _to)");
// sending tokens to the token smart contract itself is a client mistake
require(_to != address(this), "invalid recipient (transfer to the token smart contract itself)");
// according to ERC-20 Token Standard, https://eips.ethereum.org/EIPS/eip-20
// "Transfers of 0 values MUST be treated as normal transfers and fire the Transfer event."
if(_value == 0) {
// emit an ERC20 transfer event
emit Transfer(_from, _to, _value);
// don't forget to return - we're done
return;
}
// no need to make arithmetic overflow check on the _value - by design of mint()
// in case of transfer on behalf
if(_from != msg.sender) {
// read allowance value - the amount of tokens allowed to transfer - into the stack
uint256 _allowance = transferAllowances[_from][msg.sender];
// verify sender has an allowance to transfer amount of tokens requested
require(_allowance >= _value, "ERC20: transfer amount exceeds allowance"); // Zeppelin msg
// update allowance value on the stack
_allowance -= _value;
// update the allowance value in storage
transferAllowances[_from][msg.sender] = _allowance;
// emit an improved atomic approve event
emit Approved(_from, msg.sender, _allowance + _value, _allowance);
// emit an ERC20 approval event to reflect the decrease
emit Approval(_from, msg.sender, _allowance);
}
// verify sender has enough tokens to transfer on behalf
require(tokenBalances[_from] >= _value, "ERC20: transfer amount exceeds balance"); // Zeppelin msg
// perform the transfer:
// decrease token owner (sender) balance
tokenBalances[_from] -= _value;
// increase `_to` address (receiver) balance
tokenBalances[_to] += _value;
// move voting power associated with the tokens transferred
__moveVotingPower(votingDelegates[_from], votingDelegates[_to], _value);
// emit an improved transfer event
emit Transferred(msg.sender, _from, _to, _value);
// emit an ERC20 transfer event
emit Transfer(_from, _to, _value);
}
/**
* @notice Approves address called `_spender` to transfer some amount
* of tokens on behalf of the owner
*
* @dev ERC20 `function approve(address _spender, uint256 _value) public returns (bool success)`
*
* @dev Caller must not necessarily own any tokens to grant the permission
*
* @param _spender an address approved by the caller (token owner)
* to spend some tokens on its behalf
* @param _value an amount of tokens spender `_spender` is allowed to
* transfer on behalf of the token owner
* @return success true on success, throws otherwise
*/
function approve(address _spender, uint256 _value) public returns (bool success) {
// non-zero spender address check - Zeppelin
// obviously, zero spender address is a client mistake
// it's not part of ERC20 standard but it's reasonable to fail fast
require(_spender != address(0), "ERC20: approve to the zero address"); // Zeppelin msg
// read old approval value to emmit an improved event (ISBN:978-1-7281-3027-9)
uint256 _oldValue = transferAllowances[msg.sender][_spender];
// perform an operation: write value requested into the storage
transferAllowances[msg.sender][_spender] = _value;
// emit an improved atomic approve event (ISBN:978-1-7281-3027-9)
emit Approved(msg.sender, _spender, _oldValue, _value);
// emit an ERC20 approval event
emit Approval(msg.sender, _spender, _value);
// operation successful, return true
return true;
}
/**
* @notice Returns the amount which _spender is still allowed to withdraw from _owner.
*
* @dev ERC20 `function allowance(address _owner, address _spender) public view returns (uint256 remaining)`
*
* @dev A function to check an amount of tokens owner approved
* to transfer on its behalf by some other address called "spender"
*
* @param _owner an address which approves transferring some tokens on its behalf
* @param _spender an address approved to transfer some tokens on behalf
* @return remaining an amount of tokens approved address `_spender` can transfer on behalf
* of token owner `_owner`
*/
function allowance(address _owner, address _spender) public view returns (uint256 remaining) {
// read the value from storage and return
return transferAllowances[_owner][_spender];
}
// ===== End: ERC20/ERC223/ERC777 functions =====
// ===== Start: Resolution for the Multiple Withdrawal Attack on ERC20 Tokens (ISBN:978-1-7281-3027-9) =====
/**
* @notice Increases the allowance granted to `spender` by the transaction sender
*
* @dev Resolution for the Multiple Withdrawal Attack on ERC20 Tokens (ISBN:978-1-7281-3027-9)
*
* @dev Throws if value to increase by is zero or too big and causes arithmetic overflow
*
* @param _spender an address approved by the caller (token owner)
* to spend some tokens on its behalf
* @param _value an amount of tokens to increase by
* @return success true on success, throws otherwise
*/
function increaseAllowance(address _spender, uint256 _value) public virtual returns (bool) {
// read current allowance value
uint256 currentVal = transferAllowances[msg.sender][_spender];
// non-zero _value and arithmetic overflow check on the allowance
require(currentVal + _value > currentVal, "zero value approval increase or arithmetic overflow");
// delegate call to `approve` with the new value
return approve(_spender, currentVal + _value);
}
/**
* @notice Decreases the allowance granted to `spender` by the caller.
*
* @dev Resolution for the Multiple Withdrawal Attack on ERC20 Tokens (ISBN:978-1-7281-3027-9)
*
* @dev Throws if value to decrease by is zero or is bigger than currently allowed value
*
* @param _spender an address approved by the caller (token owner)
* to spend some tokens on its behalf
* @param _value an amount of tokens to decrease by
* @return success true on success, throws otherwise
*/
function decreaseAllowance(address _spender, uint256 _value) public virtual returns (bool) {
// read current allowance value
uint256 currentVal = transferAllowances[msg.sender][_spender];
// non-zero _value check on the allowance
require(_value > 0, "zero value approval decrease");
// verify allowance decrease doesn't underflow
require(currentVal >= _value, "ERC20: decreased allowance below zero");
// delegate call to `approve` with the new value
return approve(_spender, currentVal - _value);
}
// ===== End: Resolution for the Multiple Withdrawal Attack on ERC20 Tokens (ISBN:978-1-7281-3027-9) =====
// ===== Start: Minting/burning extension =====
/**
* @dev Mints (creates) some tokens to address specified
* @dev The value specified is treated as is without taking
* into account what `decimals` value is
* @dev Behaves effectively as `mintTo` function, allowing
* to specify an address to mint tokens to
* @dev Requires sender to have `ROLE_TOKEN_CREATOR` permission
*
* @dev Throws on overflow, if totalSupply + _value doesn't fit into uint256
*
* @param _to an address to mint tokens to
* @param _value an amount of tokens to mint (create)
*/
function mint(address _to, uint256 _value) public {
// check if caller has sufficient permissions to mint tokens
require(isSenderInRole(ROLE_TOKEN_CREATOR), "insufficient privileges (ROLE_TOKEN_CREATOR required)");
// non-zero recipient address check
require(_to != address(0), "ERC20: mint to the zero address"); // Zeppelin msg
// non-zero _value and arithmetic overflow check on the total supply
// this check automatically secures arithmetic overflow on the individual balance
require(totalSupply + _value > totalSupply, "zero value mint or arithmetic overflow");
// uint192 overflow check (required by voting delegation)
require(totalSupply + _value <= type(uint192).max, "total supply overflow (uint192)");
// perform mint:
// increase total amount of tokens value
totalSupply += _value;
// increase `_to` address balance
tokenBalances[_to] += _value;
// create voting power associated with the tokens minted
__moveVotingPower(address(0), votingDelegates[_to], _value);
// fire a minted event
emit Minted(msg.sender, _to, _value);
// emit an improved transfer event
emit Transferred(msg.sender, address(0), _to, _value);
// fire ERC20 compliant transfer event
emit Transfer(address(0), _to, _value);
}
/**
* @dev Burns (destroys) some tokens from the address specified
* @dev The value specified is treated as is without taking
* into account what `decimals` value is
* @dev Behaves effectively as `burnFrom` function, allowing
* to specify an address to burn tokens from
* @dev Requires sender to have `ROLE_TOKEN_DESTROYER` permission
*
* @param _from an address to burn some tokens from
* @param _value an amount of tokens to burn (destroy)
*/
function burn(address _from, uint256 _value) public {
// check if caller has sufficient permissions to burn tokens
// and if not - check for possibility to burn own tokens or to burn on behalf
if(!isSenderInRole(ROLE_TOKEN_DESTROYER)) {
// if `_from` is equal to sender, require own burns feature to be enabled
// otherwise require burns on behalf feature to be enabled
require(_from == msg.sender && isFeatureEnabled(FEATURE_OWN_BURNS)
|| _from != msg.sender && isFeatureEnabled(FEATURE_BURNS_ON_BEHALF),
_from == msg.sender? "burns are disabled": "burns on behalf are disabled");
// in case of burn on behalf
if(_from != msg.sender) {
// read allowance value - the amount of tokens allowed to be burnt - into the stack
uint256 _allowance = transferAllowances[_from][msg.sender];
// verify sender has an allowance to burn amount of tokens requested
require(_allowance >= _value, "ERC20: burn amount exceeds allowance"); // Zeppelin msg
// update allowance value on the stack
_allowance -= _value;
// update the allowance value in storage
transferAllowances[_from][msg.sender] = _allowance;
// emit an improved atomic approve event
emit Approved(msg.sender, _from, _allowance + _value, _allowance);
// emit an ERC20 approval event to reflect the decrease
emit Approval(_from, msg.sender, _allowance);
}
}
// at this point we know that either sender is ROLE_TOKEN_DESTROYER or
// we burn own tokens or on behalf (in latest case we already checked and updated allowances)
// we have left to execute balance checks and burning logic itself
// non-zero burn value check
require(_value != 0, "zero value burn");
// non-zero source address check - Zeppelin
require(_from != address(0), "ERC20: burn from the zero address"); // Zeppelin msg
// verify `_from` address has enough tokens to destroy
// (basically this is a arithmetic overflow check)
require(tokenBalances[_from] >= _value, "ERC20: burn amount exceeds balance"); // Zeppelin msg
// perform burn:
// decrease `_from` address balance
tokenBalances[_from] -= _value;
// decrease total amount of tokens value
totalSupply -= _value;
// destroy voting power associated with the tokens burnt
__moveVotingPower(votingDelegates[_from], address(0), _value);
// fire a burnt event
emit Burnt(msg.sender, _from, _value);
// emit an improved transfer event
emit Transferred(msg.sender, _from, address(0), _value);
// fire ERC20 compliant transfer event
emit Transfer(_from, address(0), _value);
}
// ===== End: Minting/burning extension =====
// ===== Start: DAO Support (Compound-like voting delegation) =====
/**
* @notice Gets current voting power of the account `_of`
* @param _of the address of account to get voting power of
* @return current cumulative voting power of the account,
* sum of token balances of all its voting delegators
*/
function getVotingPower(address _of) public view returns (uint256) {
// get a link to an array of voting power history records for an address specified
VotingPowerRecord[] storage history = votingPowerHistory[_of];
// lookup the history and return latest element
return history.length == 0? 0: history[history.length - 1].votingPower;
}
/**
* @notice Gets past voting power of the account `_of` at some block `_blockNum`
* @dev Throws if `_blockNum` is not in the past (not the finalized block)
* @param _of the address of account to get voting power of
* @param _blockNum block number to get the voting power at
* @return past cumulative voting power of the account,
* sum of token balances of all its voting delegators at block number `_blockNum`
*/
function getVotingPowerAt(address _of, uint256 _blockNum) public view returns (uint256) {
// make sure block number is not in the past (not the finalized block)
require(_blockNum < block.number, "not yet determined"); // Compound msg
// get a link to an array of voting power history records for an address specified
VotingPowerRecord[] storage history = votingPowerHistory[_of];
// if voting power history for the account provided is empty
if(history.length == 0) {
// than voting power is zero - return the result
return 0;
}
// check latest voting power history record block number:
// if history was not updated after the block of interest
if(history[history.length - 1].blockNumber <= _blockNum) {
// we're done - return last voting power record
return getVotingPower(_of);
}
// check first voting power history record block number:
// if history was never updated before the block of interest
if(history[0].blockNumber > _blockNum) {
// we're done - voting power at the block num of interest was zero
return 0;
}
// `votingPowerHistory[_of]` is an array ordered by `blockNumber`, ascending;
// apply binary search on `votingPowerHistory[_of]` to find such an entry number `i`, that
// `votingPowerHistory[_of][i].blockNumber <= _blockNum`, but in the same time
// `votingPowerHistory[_of][i + 1].blockNumber > _blockNum`
// return the result - voting power found at index `i`
return history[__binaryLookup(_of, _blockNum)].votingPower;
}
/**
* @dev Reads an entire voting power history array for the delegate specified
*
* @param _of delegate to query voting power history for
* @return voting power history array for the delegate of interest
*/
function getVotingPowerHistory(address _of) public view returns(VotingPowerRecord[] memory) {
// return an entire array as memory
return votingPowerHistory[_of];
}
/**
* @dev Returns length of the voting power history array for the delegate specified;
* useful since reading an entire array just to get its length is expensive (gas cost)
*
* @param _of delegate to query voting power history length for
* @return voting power history array length for the delegate of interest
*/
function getVotingPowerHistoryLength(address _of) public view returns(uint256) {
// read array length and return
return votingPowerHistory[_of].length;
}
/**
* @notice Delegates voting power of the delegator `msg.sender` to the delegate `_to`
*
* @dev Accepts zero value address to delegate voting power to, effectively
* removing the delegate in that case
*
* @param _to address to delegate voting power to
*/
function delegate(address _to) public {
// verify delegations are enabled
require(isFeatureEnabled(FEATURE_DELEGATIONS), "delegations are disabled");
// delegate call to `__delegate`
__delegate(msg.sender, _to);
}
/**
* @notice Delegates voting power of the delegator (represented by its signature) to the delegate `_to`
*
* @dev Accepts zero value address to delegate voting power to, effectively
* removing the delegate in that case
*
* @dev Compliant with EIP-712: Ethereum typed structured data hashing and signing,
* see https://eips.ethereum.org/EIPS/eip-712
*
* @param _to address to delegate voting power to
* @param _nonce nonce used to construct the signature, and used to validate it;
* nonce is increased by one after successful signature validation and vote delegation
* @param _exp signature expiration time
* @param v the recovery byte of the signature
* @param r half of the ECDSA signature pair
* @param s half of the ECDSA signature pair
*/
function delegateWithSig(address _to, uint256 _nonce, uint256 _exp, uint8 v, bytes32 r, bytes32 s) public {
// verify delegations on behalf are enabled
require(isFeatureEnabled(FEATURE_DELEGATIONS_ON_BEHALF), "delegations on behalf are disabled");
// build the EIP-712 contract domain separator
bytes32 domainSeparator = keccak256(abi.encode(DOMAIN_TYPEHASH, keccak256(bytes(name)), block.chainid, address(this)));
// build the EIP-712 hashStruct of the delegation message
bytes32 hashStruct = keccak256(abi.encode(DELEGATION_TYPEHASH, _to, _nonce, _exp));
// calculate the EIP-712 digest "\x19\x01" ‖ domainSeparator ‖ hashStruct(message)
bytes32 digest = keccak256(abi.encodePacked("\x19\x01", domainSeparator, hashStruct));
// recover the address who signed the message with v, r, s
address signer = ecrecover(digest, v, r, s);
// perform message integrity and security validations
require(signer != address(0), "invalid signature"); // Compound msg
require(_nonce == nonces[signer], "invalid nonce"); // Compound msg
require(block.timestamp < _exp, "signature expired"); // Compound msg
// update the nonce for that particular signer to avoid replay attack
nonces[signer]++;
// delegate call to `__delegate` - execute the logic required
__delegate(signer, _to);
}
/**
* @dev Auxiliary function to delegate delegator's `_from` voting power to the delegate `_to`
* @dev Writes to `votingDelegates` and `votingPowerHistory` mappings
*
* @param _from delegator who delegates his voting power
* @param _to delegate who receives the voting power
*/
function __delegate(address _from, address _to) private {
// read current delegate to be replaced by a new one
address _fromDelegate = votingDelegates[_from];
// read current voting power (it is equal to token balance)
uint256 _value = tokenBalances[_from];
// reassign voting delegate to `_to`
votingDelegates[_from] = _to;
// update voting power for `_fromDelegate` and `_to`
__moveVotingPower(_fromDelegate, _to, _value);
// emit an event
emit DelegateChanged(_from, _fromDelegate, _to);
}
/**
* @dev Auxiliary function to move voting power `_value`
* from delegate `_from` to the delegate `_to`
*
* @dev Doesn't have any effect if `_from == _to`, or if `_value == 0`
*
* @param _from delegate to move voting power from
* @param _to delegate to move voting power to
* @param _value voting power to move from `_from` to `_to`
*/
function __moveVotingPower(address _from, address _to, uint256 _value) private {
// if there is no move (`_from == _to`) or there is nothing to move (`_value == 0`)
if(_from == _to || _value == 0) {
// return silently with no action
return;
}
// if source address is not zero - decrease its voting power
if(_from != address(0)) {
// read current source address voting power
uint256 _fromVal = getVotingPower(_from);
// calculate decreased voting power
// underflow is not possible by design:
// voting power is limited by token balance which is checked by the callee
uint256 _toVal = _fromVal - _value;
// update source voting power from `_fromVal` to `_toVal`
__updateVotingPower(_from, _fromVal, _toVal);
}
// if destination address is not zero - increase its voting power
if(_to != address(0)) {
// read current destination address voting power
uint256 _fromVal = getVotingPower(_to);
// calculate increased voting power
// overflow is not possible by design:
// max token supply limits the cumulative voting power
uint256 _toVal = _fromVal + _value;
// update destination voting power from `_fromVal` to `_toVal`
__updateVotingPower(_to, _fromVal, _toVal);
}
}
/**
* @dev Auxiliary function to update voting power of the delegate `_of`
* from value `_fromVal` to value `_toVal`
*
* @param _of delegate to update its voting power
* @param _fromVal old voting power of the delegate
* @param _toVal new voting power of the delegate
*/
function __updateVotingPower(address _of, uint256 _fromVal, uint256 _toVal) private {
// get a link to an array of voting power history records for an address specified
VotingPowerRecord[] storage history = votingPowerHistory[_of];
// if there is an existing voting power value stored for current block
if(history.length != 0 && history[history.length - 1].blockNumber == block.number) {
// update voting power which is already stored in the current block
history[history.length - 1].votingPower = uint192(_toVal);
}
// otherwise - if there is no value stored for current block
else {
// add new element into array representing the value for current block
history.push(VotingPowerRecord(uint64(block.number), uint192(_toVal)));
}
// emit an event
emit VotingPowerChanged(_of, _fromVal, _toVal);
}
/**
* @dev Auxiliary function to lookup an element in a sorted (asc) array of elements
*
* @dev This function finds the closest element in an array to the value
* of interest (not exceeding that value) and returns its index within an array
*
* @dev An array to search in is `votingPowerHistory[_to][i].blockNumber`,
* it is sorted in ascending order (blockNumber increases)
*
* @param _to an address of the delegate to get an array for
* @param n value of interest to look for
* @return an index of the closest element in an array to the value
* of interest (not exceeding that value)
*/
function __binaryLookup(address _to, uint256 n) private view returns(uint256) {
// get a link to an array of voting power history records for an address specified
VotingPowerRecord[] storage history = votingPowerHistory[_to];
// left bound of the search interval, originally start of the array
uint256 i = 0;
// right bound of the search interval, originally end of the array
uint256 j = history.length - 1;
// the iteration process narrows down the bounds by
// splitting the interval in a half oce per each iteration
while(j > i) {
// get an index in the middle of the interval [i, j]
uint256 k = j - (j - i) / 2;
// read an element to compare it with the value of interest
VotingPowerRecord memory cp = history[k];
// if we've got a strict equal - we're lucky and done
if(cp.blockNumber == n) {
// just return the result - index `k`
return k;
}
// if the value of interest is bigger - move left bound to the middle
else if (cp.blockNumber < n) {
// move left bound `i` to the middle position `k`
i = k;
}
// otherwise, when the value of interest is smaller - move right bound to the middle
else {
// move right bound `j` to the middle position `k - 1`:
// element at position `k` is bigger and cannot be the result
j = k - 1;
}
}
// reaching that point means no exact match found
// since we're interested in the element which is not bigger than the
// element of interest, we return the lower bound `i`
return i;
}
}
// ===== End: DAO Support (Compound-like voting delegation) =====
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
/**
* @title Address Utils
*
* @dev Utility library of inline functions on addresses
*
* @author Basil Gorin
*/
library AddressUtils {
/**
* @notice Checks if the target address is a contract
* @dev This function will return false if invoked during the constructor of a contract,
* as the code is not actually created until after the constructor finishes.
* @param addr address to check
* @return whether the target address is a contract
*/
function isContract(address addr) internal view returns (bool) {
// a variable to load `extcodesize` to
uint256 size = 0;
// XXX Currently there is no better way to check if there is a contract in an address
// than to check the size of the code at that address.
// See https://ethereum.stackexchange.com/a/14016/36603 for more details about how this works.
// TODO: Check this again before the Serenity release, because all addresses will be contracts.
// solium-disable-next-line security/no-inline-assembly
assembly {
// retrieve the size of the code at address `addr`
size := extcodesize(addr)
}
// positive size indicates a smart contract address
return size > 0;
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
/**
* @title Access Control List
*
* @notice Access control smart contract provides an API to check
* if specific operation is permitted globally and/or
* if particular user has a permission to execute it.
*
* @notice It deals with two main entities: features and roles.
*
* @notice Features are designed to be used to enable/disable specific
* functions (public functions) of the smart contract for everyone.
* @notice User roles are designed to restrict access to specific
* functions (restricted functions) of the smart contract to some users.
*
* @notice Terms "role", "permissions" and "set of permissions" have equal meaning
* in the documentation text and may be used interchangeably.
* @notice Terms "permission", "single permission" implies only one permission bit set.
*
* @dev This smart contract is designed to be inherited by other
* smart contracts which require access control management capabilities.
*
* @author Basil Gorin
*/
contract AccessControl {
/**
* @notice Access manager is responsible for assigning the roles to users,
* enabling/disabling global features of the smart contract
* @notice Access manager can add, remove and update user roles,
* remove and update global features
*
* @dev Role ROLE_ACCESS_MANAGER allows modifying user roles and global features
* @dev Role ROLE_ACCESS_MANAGER has single bit at position 255 enabled
*/
uint256 public constant ROLE_ACCESS_MANAGER = 0x8000000000000000000000000000000000000000000000000000000000000000;
/**
* @dev Bitmask representing all the possible permissions (super admin role)
* @dev Has all the bits are enabled (2^256 - 1 value)
*/
uint256 private constant FULL_PRIVILEGES_MASK = type(uint256).max; // before 0.8.0: uint256(-1) overflows to 0xFFFF...
/**
* @notice Privileged addresses with defined roles/permissions
* @notice In the context of ERC20/ERC721 tokens these can be permissions to
* allow minting or burning tokens, transferring on behalf and so on
*
* @dev Maps user address to the permissions bitmask (role), where each bit
* represents a permission
* @dev Bitmask 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
* represents all possible permissions
* @dev Zero address mapping represents global features of the smart contract
*/
mapping(address => uint256) public userRoles;
/**
* @dev Fired in updateRole() and updateFeatures()
*
* @param _by operator which called the function
* @param _to address which was granted/revoked permissions
* @param _requested permissions requested
* @param _actual permissions effectively set
*/
event RoleUpdated(address indexed _by, address indexed _to, uint256 _requested, uint256 _actual);
/**
* @notice Creates an access control instance,
* setting contract creator to have full privileges
*/
constructor() {
// contract creator has full privileges
userRoles[msg.sender] = FULL_PRIVILEGES_MASK;
}
/**
* @notice Retrieves globally set of features enabled
*
* @dev Auxiliary getter function to maintain compatibility with previous
* versions of the Access Control List smart contract, where
* features was a separate uint256 public field
*
* @return 256-bit bitmask of the features enabled
*/
function features() public view returns(uint256) {
// according to new design features are stored in zero address
// mapping of `userRoles` structure
return userRoles[address(0)];
}
/**
* @notice Updates set of the globally enabled features (`features`),
* taking into account sender's permissions
*
* @dev Requires transaction sender to have `ROLE_ACCESS_MANAGER` permission
* @dev Function is left for backward compatibility with older versions
*
* @param _mask bitmask representing a set of features to enable/disable
*/
function updateFeatures(uint256 _mask) public {
// delegate call to `updateRole`
updateRole(address(0), _mask);
}
/**
* @notice Updates set of permissions (role) for a given user,
* taking into account sender's permissions.
*
* @dev Setting role to zero is equivalent to removing an all permissions
* @dev Setting role to `FULL_PRIVILEGES_MASK` is equivalent to
* copying senders' permissions (role) to the user
* @dev Requires transaction sender to have `ROLE_ACCESS_MANAGER` permission
*
* @param operator address of a user to alter permissions for or zero
* to alter global features of the smart contract
* @param role bitmask representing a set of permissions to
* enable/disable for a user specified
*/
function updateRole(address operator, uint256 role) public {
// caller must have a permission to update user roles
require(isSenderInRole(ROLE_ACCESS_MANAGER), "insufficient privileges (ROLE_ACCESS_MANAGER required)");
// evaluate the role and reassign it
userRoles[operator] = evaluateBy(msg.sender, userRoles[operator], role);
// fire an event
emit RoleUpdated(msg.sender, operator, role, userRoles[operator]);
}
/**
* @notice Determines the permission bitmask an operator can set on the
* target permission set
* @notice Used to calculate the permission bitmask to be set when requested
* in `updateRole` and `updateFeatures` functions
*
* @dev Calculated based on:
* 1) operator's own permission set read from userRoles[operator]
* 2) target permission set - what is already set on the target
* 3) desired permission set - what do we want set target to
*
* @dev Corner cases:
* 1) Operator is super admin and its permission set is `FULL_PRIVILEGES_MASK`:
* `desired` bitset is returned regardless of the `target` permission set value
* (what operator sets is what they get)
* 2) Operator with no permissions (zero bitset):
* `target` bitset is returned regardless of the `desired` value
* (operator has no authority and cannot modify anything)
*
* @dev Example:
* Consider an operator with the permissions bitmask 00001111
* is about to modify the target permission set 01010101
* Operator wants to set that permission set to 00110011
* Based on their role, an operator has the permissions
* to update only lowest 4 bits on the target, meaning that
* high 4 bits of the target set in this example is left
* unchanged and low 4 bits get changed as desired: 01010011
*
* @param operator address of the contract operator which is about to set the permissions
* @param target input set of permissions to operator is going to modify
* @param desired desired set of permissions operator would like to set
* @return resulting set of permissions given operator will set
*/
function evaluateBy(address operator, uint256 target, uint256 desired) public view returns(uint256) {
// read operator's permissions
uint256 p = userRoles[operator];
// taking into account operator's permissions,
// 1) enable the permissions desired on the `target`
target |= p & desired;
// 2) disable the permissions desired on the `target`
target &= FULL_PRIVILEGES_MASK ^ (p & (FULL_PRIVILEGES_MASK ^ desired));
// return calculated result
return target;
}
/**
* @notice Checks if requested set of features is enabled globally on the contract
*
* @param required set of features to check against
* @return true if all the features requested are enabled, false otherwise
*/
function isFeatureEnabled(uint256 required) public view returns(bool) {
// delegate call to `__hasRole`, passing `features` property
return __hasRole(features(), required);
}
/**
* @notice Checks if transaction sender `msg.sender` has all the permissions required
*
* @param required set of permissions (role) to check against
* @return true if all the permissions requested are enabled, false otherwise
*/
function isSenderInRole(uint256 required) public view returns(bool) {
// delegate call to `isOperatorInRole`, passing transaction sender
return isOperatorInRole(msg.sender, required);
}
/**
* @notice Checks if operator has all the permissions (role) required
*
* @param operator address of the user to check role for
* @param required set of permissions (role) to check
* @return true if all the permissions requested are enabled, false otherwise
*/
function isOperatorInRole(address operator, uint256 required) public view returns(bool) {
// delegate call to `__hasRole`, passing operator's permissions (role)
return __hasRole(userRoles[operator], required);
}
/**
* @dev Checks if role `actual` contains all the permissions required `required`
*
* @param actual existent role
* @param required required role
* @return true if actual has required role (all permissions), false otherwise
*/
function __hasRole(uint256 actual, uint256 required) internal pure returns(bool) {
// check the bitmask for the role required and return the result
return actual & required == required;
}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
/**
* @title ERC20 token receiver interface
*
* @dev Interface for any contract that wants to support safe transfers
* from ERC20 token smart contracts.
* @dev Inspired by ERC721 and ERC223 token standards
*
* @dev See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
* @dev See https://github.com/ethereum/EIPs/issues/223
*
* @author Basil Gorin
*/
interface ERC20Receiver {
/**
* @notice Handle the receipt of a ERC20 token(s)
* @dev The ERC20 smart contract calls this function on the recipient
* after a successful transfer (`safeTransferFrom`).
* This function MAY throw to revert and reject the transfer.
* Return of other than the magic value MUST result in the transaction being reverted.
* @notice The contract address is always the message sender.
* A wallet/broker/auction application MUST implement the wallet interface
* if it will accept safe transfers.
* @param _operator The address which called `safeTransferFrom` function
* @param _from The address which previously owned the token
* @param _value amount of tokens which is being transferred
* @param _data additional data with no specified format
* @return `bytes4(keccak256("onERC20Received(address,address,uint256,bytes)"))` unless throwing
*/
function onERC20Received(address _operator, address _from, uint256 _value, bytes calldata _data) external returns(bytes4);
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
import "../interfaces/IERC20.sol";
/**
* @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}.
*/
// Copied from Open Zeppelin
contract ERC20 is IERC20 {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
uint8 private _decimals;
/**
* @notice Token creator is responsible for creating (minting)
* tokens to an arbitrary address
* @dev Role ROLE_TOKEN_CREATOR allows minting tokens
* (calling `mint` function)
*/
uint32 public constant ROLE_TOKEN_CREATOR = 0x0001_0000;
/**
* @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_) {
_name = name_;
_symbol = symbol_;
_decimals = 18;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual 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() public view virtual returns (uint8) {
return _decimals;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual 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(msg.sender, 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(msg.sender, 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, msg.sender, _allowances[sender][msg.sender] - amount);
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(msg.sender, spender, _allowances[msg.sender][spender] + 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(msg.sender, spender, _allowances[msg.sender][spender] - subtractedValue);
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] - amount;
_balances[recipient] = _balances[recipient] + 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 + amount;
_balances[account] = _balances[account] + 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] - amount;
_totalSupply = _totalSupply - amount;
emit Transfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This 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 virtual {
_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 {}
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
/**
* @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);
}
// SPDX-License-Identifier: MIT
pragma solidity 0.8.1;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
// solhint-disable-next-line no-inline-assembly
assembly {
size := extcodesize(account)
}
return size > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value
) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value,
string memory errorMessage
) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.3._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.3._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.delegatecall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function _verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) private pure returns (bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}