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Purpose

MellowACL is a lightweight but extendable access control layer that wraps OpenZeppelin’s AccessControlEnumerableUpgradeable. It introduces automatic tracking and enumeration of active roles to improve governance transparency. This contract is intended to be inherited by modules that require dynamic role management and storage-isolated initialization.

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Responsibilities

  • Grant and revoke access control roles to addresses
  • Keep track of all active (i.e., assigned) roles in a dedicated set
  • Expose enumerable functions for external auditing of granted roles
  • Emit structured events when roles are added or fully revoked

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Storage Layout

  • supportedRoles: A unique set of role identifiers (bytes32) currently assigned to any address
  • Uses a dedicated storage slot derived from:

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View Functions

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supportedRoles() → uint256

Returns the number of currently active roles (i.e., roles with at least one member).

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supportedRoleAt(index: uint256) → bytes32

Returns the role identifier at the specified index from the active role set.

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hasSupportedRole(role: bytes32) → bool

Returns true if the role is currently active (i.e., assigned to at least one account).

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Internal Logic

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_grantRole(role: bytes32, account: address) → bool

Grants the specified role to an account. If the role was not previously active, it is added to supportedRoles, and RoleAdded is emitted.
  • Inherits from AccessControlUpgradeable._grantRole
  • Emits:

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_revokeRole(role: bytes32, account: address) → bool

Revokes the specified role from an account. If the role has no remaining members afterward, it is removed from supportedRoles, and RoleRemoved is emitted.
  • Inherits from AccessControlUpgradeable._revokeRole
  • Emits:

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Constructor

  • Computes a deterministic storage slot using SlotLibrary
  • Disables initializer to prevent accidental direct deployment
  • Should be initialized later via proxy-aware module constructor

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Events

  • event RoleAdded(bytes32 indexed role)
    • Emitted when a new role is introduced into the system
  • event RoleRemoved(bytes32 indexed role)
    • Emitted when the last holder of a role is revoked and the role becomes inactive