Contract Name:
IlluviumERC20
Contract Source Code:
// 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 "../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 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 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;
}
}