# AccessControl

*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.*

## Methods

### DEFAULT\_ADMIN\_ROLE

```solidity
function DEFAULT_ADMIN_ROLE() external view returns (bytes32)
```

#### Returns

| Name | Type    | Description |
| ---- | ------- | ----------- |
| \_0  | bytes32 | undefined   |

### getRoleAdmin

```solidity
function getRoleAdmin(bytes32 role) external view returns (bytes32)
```

*Returns the admin role that controls `role`. See {grantRole} and {revokeRole}. To change a role's admin, use {\_setRoleAdmin}.*

#### Parameters

| Name | Type    | Description |
| ---- | ------- | ----------- |
| role | bytes32 | undefined   |

#### Returns

| Name | Type    | Description |
| ---- | ------- | ----------- |
| \_0  | bytes32 | undefined   |

### grantRole

```solidity
function grantRole(bytes32 role, address account) external nonpayable
```

*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.*

#### Parameters

| Name    | Type    | Description |
| ------- | ------- | ----------- |
| role    | bytes32 | undefined   |
| account | address | undefined   |

### hasRole

```solidity
function hasRole(bytes32 role, address account) external view returns (bool)
```

*Returns `true` if `account` has been granted `role`.*

#### Parameters

| Name    | Type    | Description |
| ------- | ------- | ----------- |
| role    | bytes32 | undefined   |
| account | address | undefined   |

#### Returns

| Name | Type | Description |
| ---- | ---- | ----------- |
| \_0  | bool | undefined   |

### renounceRole

```solidity
function renounceRole(bytes32 role, address account) external nonpayable
```

*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 revoked `role`, emits a {RoleRevoked} event. Requirements: - the caller must be `account`.*

#### Parameters

| Name    | Type    | Description |
| ------- | ------- | ----------- |
| role    | bytes32 | undefined   |
| account | address | undefined   |

### revokeRole

```solidity
function revokeRole(bytes32 role, address account) external nonpayable
```

*Revokes `role` from `account`. If `account` had been granted `role`, emits a {RoleRevoked} event. Requirements: - the caller must have `role`'s admin role.*

#### Parameters

| Name    | Type    | Description |
| ------- | ------- | ----------- |
| role    | bytes32 | undefined   |
| account | address | undefined   |

### supportsInterface

```solidity
function supportsInterface(bytes4 interfaceId) external view returns (bool)
```

*See {IERC165-supportsInterface}.*

#### Parameters

| Name        | Type   | Description |
| ----------- | ------ | ----------- |
| interfaceId | bytes4 | undefined   |

#### Returns

| Name | Type | Description |
| ---- | ---- | ----------- |
| \_0  | bool | undefined   |

## Events

### RoleAdminChanged

```solidity
event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole)
```

#### Parameters

| Name                        | Type    | Description |
| --------------------------- | ------- | ----------- |
| role `indexed`              | bytes32 | undefined   |
| previousAdminRole `indexed` | bytes32 | undefined   |
| newAdminRole `indexed`      | bytes32 | undefined   |

### RoleGranted

```solidity
event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender)
```

#### Parameters

| Name              | Type    | Description |
| ----------------- | ------- | ----------- |
| role `indexed`    | bytes32 | undefined   |
| account `indexed` | address | undefined   |
| sender `indexed`  | address | undefined   |

### RoleRevoked

```solidity
event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender)
```

#### Parameters

| Name              | Type    | Description |
| ----------------- | ------- | ----------- |
| role `indexed`    | bytes32 | undefined   |
| account `indexed` | address | undefined   |
| sender `indexed`  | address | undefined   |