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cairoeth
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ernestognw
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Add ERC20 stablecoin extensions (#14)
* Add `ERC20Blocklist` base * Add `ERC20Allowlist` base * Add `ERC20Blocklist` base * Add allowlist and blocklist tests * Add custodian tests * Apply suggestions from code review Co-authored-by: Ernesto García <[email protected]> * Apply suggestions from code review Co-authored-by: Ernesto García <[email protected]> * Apply suggestions from code review Co-authored-by: Ernesto García <[email protected]> * Apply suggestions from code review Co-authored-by: Ernesto García <[email protected]> * Apply suggestions from code review Co-authored-by: Ernesto García <[email protected]> * Apply suggestions from code review Co-authored-by: Ernesto García <[email protected]> * Apply suggestions from code review Co-authored-by: Ernesto García <[email protected]> * Update allowlist based on feedback * Update other extensions and tests * Apply suggestions from code review Co-authored-by: Ernesto García <[email protected]> * Update block/unblock functions * Combine freeze functions --------- Co-authored-by: Ernesto García <[email protected]>
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‎contracts/mocks/token/ERC20CustodianMock.sol

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// SPDX-License-Identifier: MIT
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pragma solidity ^0.8.20;
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import {ERC20, ERC20Custodian} from "../../token/ERC20/extensions/ERC20Custodian.sol";
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abstract contract ERC20CustodianMock is ERC20Custodian {
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address private immutable _custodian;
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constructor(address custodian, string memory name_, string memory symbol_) ERC20(name_, symbol_) {
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_custodian = custodian;
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}
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function _isCustodian(address user) internal view override returns (bool) {
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return user == _custodian;
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}
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}

‎contracts/token/ERC20/extensions/ERC20Allowlist.sol

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// SPDX-License-Identifier: MIT
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pragma solidity ^0.8.20;
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import {ERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
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/**
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* @dev Extension of {ERC20} that allows to implement an allowlist
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* mechanism that can be managed by an authorized account with the
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* {_disallowUser} and {_allowUser} functions.
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*
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* The allowlist provides the guarantee to the contract owner
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* (e.g. a DAO or a well-configured multisig) that any account won't be
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* able to execute transfers or approvals to other entities to operate
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* on its behalf if {_allowUser} was not called with such account as an
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* argument. Similarly, the account will be disallowed again if
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* {_disallowUser} is called.
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*/
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abstract contract ERC20Allowlist is ERC20 {
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/**
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* @dev Allowed status of addresses. True if allowed, False otherwise.
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*/
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mapping(address account => bool) internal _allowed;
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/**
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* @dev Emitted when a `user` is allowed to transfer and approve.
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*/
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event UserAllowed(address indexed user);
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/**
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* @dev Emitted when a user is disallowed.
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*/
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event UserDisallowed(address indexed user);
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/**
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* @dev The operation failed because the user is not allowed.
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*/
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error ERC20Disallowed(address user);
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/**
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* @dev Returns the allowed status of an account.
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*/
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function allowed(address account) public virtual returns (bool) {
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return _allowed[account];
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}
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/**
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* @dev Allows a user to receive and transfer tokens, including minting and burning.
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*/
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function _allowUser(address user) internal virtual returns (bool) {
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bool isAllowed = allowed(user);
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if (!isAllowed) {
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_allowed[user] = true;
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emit UserAllowed(user);
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}
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return isAllowed;
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}
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/**
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* @dev Disallows a user from receiving and transferring tokens, including minting and burning.
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*/
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function _disallowUser(address user) internal virtual returns (bool) {
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bool isAllowed = allowed(user);
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if (isAllowed) {
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_allowed[user] = false;
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emit UserDisallowed(user);
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}
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return isAllowed;
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}
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/**
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* @dev See {ERC20-_update}.
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*/
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function _update(address from, address to, uint256 value) internal virtual override {
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if (from != address(0) && !allowed(from)) revert ERC20Disallowed(from);
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if (to != address(0) && !allowed(to)) revert ERC20Disallowed(to);
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super._update(from, to, value);
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}
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/**
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* @dev See {ERC20-_approve}.
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*/
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function _approve(address owner, address spender, uint256 value, bool emitEvent) internal virtual override {
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if (!allowed(owner)) revert ERC20Disallowed(owner);
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super._approve(owner, spender, value, emitEvent);
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}
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}

‎contracts/token/ERC20/extensions/ERC20Blocklist.sol

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// SPDX-License-Identifier: MIT
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pragma solidity ^0.8.20;
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import {ERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
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/**
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* @dev Extension of {ERC20} that allows to implement a blocklist
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* mechanism that can be managed by an authorized account with the
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* {_blockUser} and {_unblockUser} functions.
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*
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* The blocklist provides the guarantee to the contract owner
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* (e.g. a DAO or a well-configured multisig) that any account won't be
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* able to execute transfers or approvals to other entities to operate
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* on its behalf if {_blockUser} was not called with such account as an
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* argument. Similarly, the account will be unblocked again if
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* {_unblockUser} is called.
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*/
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abstract contract ERC20Blocklist is ERC20 {
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/**
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* @dev Blocked status of addresses. True if blocked, False otherwise.
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*/
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mapping(address user => bool) internal _blocked;
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/**
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* @dev Emitted when a user is blocked.
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*/
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event UserBlocked(address indexed user);
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/**
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* @dev Emitted when a user is unblocked.
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*/
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event UserUnblocked(address indexed user);
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/**
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* @dev The operation failed because the user is blocked.
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*/
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error ERC20Blocked(address user);
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/**
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* @dev Returns the blocked status of an account.
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*/
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function blocked(address account) public virtual returns (bool) {
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return _blocked[account];
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}
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/**
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* @dev Blocks a user from receiving and transferring tokens, including minting and burning.
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*/
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function _blockUser(address user) internal virtual returns (bool) {
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bool isBlocked = blocked(user);
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if (!isBlocked) {
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_blocked[user] = true;
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emit UserBlocked(user);
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}
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return isBlocked;
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}
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/**
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* @dev Unblocks a user from receiving and transferring tokens, including minting and burning.
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*/
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function _unblockUser(address user) internal virtual returns (bool) {
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bool isBlocked = blocked(user);
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if (isBlocked) {
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_blocked[user] = false;
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emit UserUnblocked(user);
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}
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return isBlocked;
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}
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/**
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* @dev See {ERC20-_update}.
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*/
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function _update(address from, address to, uint256 value) internal virtual override {
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if (blocked(from)) revert ERC20Blocked(from);
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if (blocked(to)) revert ERC20Blocked(to);
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super._update(from, to, value);
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}
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/**
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* @dev See {ERC20-_approve}.
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*/
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function _approve(address owner, address spender, uint256 value, bool emitEvent) internal virtual override {
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if (blocked(owner)) revert ERC20Blocked(owner);
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super._approve(owner, spender, value, emitEvent);
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}
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}

‎contracts/token/ERC20/extensions/ERC20Custodian.sol

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// SPDX-License-Identifier: MIT
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pragma solidity ^0.8.20;
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import {ERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
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/**
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* @dev Extension of {ERC20} that allows to implement a custodian
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* mechanism that can be managed by an authorized account with the
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* {freeze} and {unfreeze} functions.
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*
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* This mechanism allows a custodian (e.g. a DAO or a
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* well-configured multisig) to freeze and unfreeze the balance
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* of a user.
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*
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* The frozen balance is not available for transfers or approvals
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* to other entities to operate on its behalf if {freeze} was not
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* called with such account as an argument. Similarly, the account
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* will be unfrozen again if {unfreeze} is called.
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*/
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abstract contract ERC20Custodian is ERC20 {
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/**
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* @dev The amount of tokens frozen by user address.
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*/
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mapping(address user => uint256 amount) internal _frozen;
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/**
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* @dev Emitted when tokens are frozen for a user.
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* @param user The address of the user whose tokens were frozen.
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* @param amount The amount of tokens that were frozen.
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*/
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event TokensFrozen(address indexed user, uint256 amount);
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/**
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* @dev Emitted when tokens are unfrozen for a user.
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* @param user The address of the user whose tokens were unfrozen.
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* @param amount The amount of tokens that were unfrozen.
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*/
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event TokensUnfrozen(address indexed user, uint256 amount);
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/**
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* @dev The operation failed because the user has insufficient unfrozen balance.
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*/
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error ERC20InsufficientUnfrozenBalance(address user);
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/**
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* @dev The operation failed because the user has insufficient frozen balance.
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*/
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error ERC20InsufficientFrozenBalance(address user);
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/**
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* @dev Error thrown when a non-custodian account attempts to perform a custodian-only operation.
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*/
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error ERC20NotCustodian();
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/**
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* @dev Modifier to restrict access to custodian accounts only.
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*/
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modifier onlyCustodian() {
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if (!_isCustodian(_msgSender())) revert ERC20NotCustodian();
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_;
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}
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/**
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* @dev Returns the amount of tokens frozen for a user.
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*/
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function frozen(address user) public view virtual returns (uint256) {
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return _frozen[user];
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}
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/**
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* @dev Adjusts the amount of tokens frozen for a user.
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* @param user The address of the user whose tokens to freeze.
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* @param amount The amount of tokens frozen.
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*
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* Requirements:
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*
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* - The user must have sufficient unfrozen balance.
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*/
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function freeze(address user, uint256 amount) external virtual onlyCustodian {
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if (availableBalance(user) < amount) revert ERC20InsufficientUnfrozenBalance(user);
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_frozen[user] = amount;
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emit TokensFrozen(user, amount);
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}
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/**
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* @dev Returns the available (unfrozen) balance of an account.
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* @param account The address to query the available balance of.
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* @return available The amount of tokens available for transfer.
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*/
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function availableBalance(address account) public view returns (uint256 available) {
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available = balanceOf(account) - frozen(account);
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}
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/**
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* @dev Checks if the user is a custodian.
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* @param user The address of the user to check.
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* @return True if the user is authorized, false otherwise.
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*/
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function _isCustodian(address user) internal view virtual returns (bool);
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function _update(address from, address to, uint256 value) internal virtual override {
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if (from != address(0) && availableBalance(from) < value) revert ERC20InsufficientUnfrozenBalance(from);
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super._update(from, to, value);
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}
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}

‎contracts/token/ERC4626Fees.sol renamed to ‎contracts/token/ERC20/extensions/ERC4626Fees.sol

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