AccessControl.sol

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.10;

import './IAccessControl.sol';
import './Context.sol';
import './Strings.sol';
import './ERC165.sol';

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context, IAccessControl, ERC165 {
  struct RoleData {
    mapping(address => bool) members;
    bytes32 adminRole;
  }

  mapping(bytes32 => RoleData) private _roles;

  bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

  /**
   * @dev Modifier that checks that an account has a specific role. Reverts
   * with a standardized message including the required role.
   *
   * The format of the revert reason is given by the following regular expression:
   *
   *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
   *
   * _Available since v4.1._
   */
  modifier onlyRole(bytes32 role) {
    _checkRole(role, _msgSender());
    _;
  }

  /**
   * @dev See {IERC165-supportsInterface}.
   */
  function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
    return interfaceId == type(IAccessControl).interfaceId || super.supportsInterface(interfaceId);
  }

  /**
   * @dev Returns `true` if `account` has been granted `role`.
   */
  function hasRole(bytes32 role, address account) public view override returns (bool) {
    return _roles[role].members[account];
  }

  /**
   * @dev Revert with a standard message if `account` is missing `role`.
   *
   * The format of the revert reason is given by the following regular expression:
   *
   *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
   */
  function _checkRole(bytes32 role, address account) internal view {
    if (!hasRole(role, account)) {
      revert(
        string(
          abi.encodePacked(
            'AccessControl: account ',
            Strings.toHexString(uint160(account), 20),
            ' is missing role ',
            Strings.toHexString(uint256(role), 32)
          )
        )
      );
    }
  }

  /**
   * @dev Returns the admin role that controls `role`. See {grantRole} and
   * {revokeRole}.
   *
   * To change a role's admin, use {_setRoleAdmin}.
   */
  function getRoleAdmin(bytes32 role) public view override returns (bytes32) {
    return _roles[role].adminRole;
  }

  /**
   * @dev Grants `role` to `account`.
   *
   * If `account` had not been already granted `role`, emits a {RoleGranted}
   * event.
   *
   * Requirements:
   *
   * - the caller must have ``role``'s admin role.
   */
  function grantRole(
    bytes32 role,
    address account
  ) public virtual override onlyRole(getRoleAdmin(role)) {
    _grantRole(role, account);
  }

  /**
   * @dev Revokes `role` from `account`.
   *
   * If `account` had been granted `role`, emits a {RoleRevoked} event.
   *
   * Requirements:
   *
   * - the caller must have ``role``'s admin role.
   */
  function revokeRole(
    bytes32 role,
    address account
  ) public virtual override onlyRole(getRoleAdmin(role)) {
    _revokeRole(role, account);
  }

  /**
   * @dev Revokes `role` from the calling account.
   *
   * Roles are often managed via {grantRole} and {revokeRole}: this function's
   * purpose is to provide a mechanism for accounts to lose their privileges
   * if they are compromised (such as when a trusted device is misplaced).
   *
   * If the calling account had been granted `role`, emits a {RoleRevoked}
   * event.
   *
   * Requirements:
   *
   * - the caller must be `account`.
   */
  function renounceRole(bytes32 role, address account) public virtual override {
    require(account == _msgSender(), 'AccessControl: can only renounce roles for self');

    _revokeRole(role, account);
  }

  /**
   * @dev Grants `role` to `account`.
   *
   * If `account` had not been already granted `role`, emits a {RoleGranted}
   * event. Note that unlike {grantRole}, this function doesn't perform any
   * checks on the calling account.
   *
   * [WARNING]
   * ====
   * This function should only be called from the constructor when setting
   * up the initial roles for the system.
   *
   * Using this function in any other way is effectively circumventing the admin
   * system imposed by {AccessControl}.
   * ====
   */
  function _setupRole(bytes32 role, address account) internal virtual {
    _grantRole(role, account);
  }

  /**
   * @dev Sets `adminRole` as ``role``'s admin role.
   *
   * Emits a {RoleAdminChanged} event.
   */
  function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
    bytes32 previousAdminRole = getRoleAdmin(role);
    _roles[role].adminRole = adminRole;
    emit RoleAdminChanged(role, previousAdminRole, adminRole);
  }

  function _grantRole(bytes32 role, address account) private {
    if (!hasRole(role, account)) {
      _roles[role].members[account] = true;
      emit RoleGranted(role, account, _msgSender());
    }
  }

  function _revokeRole(bytes32 role, address account) private {
    if (hasRole(role, account)) {
      _roles[role].members[account] = false;
      emit RoleRevoked(role, account, _msgSender());
    }
  }
}