Base IModule

Overview

The Core Module Interface (IModule) serves as the foundation for all module types in the ERC-7579 smart account system. All specialized modules (Validator, Executor, Hook, Fallback) must implement this base interface.

Interface Definition

interface IModule {
    error AlreadyInitialized(address smartAccount);
    error NotInitialized(address smartAccount);

    function onInstall(bytes calldata data) external;
    function onUninstall(bytes calldata data) external;
    function isModuleType(uint256 moduleTypeId) external view returns (bool);
    function isInitialized(address smartAccount) external view returns (bool);
}

Core Functions

onInstall

Called when installing the module on a smart account.

function onInstall(bytes calldata data) external;

• Must revert if module is already initialized
• Handles initialization logic using provided data
• Typically sets up initial state for the account

onUninstall

Called when removing the module from a smart account.

function onUninstall(bytes calldata data) external;

• Must revert if module is not initialized
• Handles cleanup and state removal
• Ensures proper module deactivation

isModuleType

Verifies if the module matches a specific type.

function isModuleType(uint256 moduleTypeId) external view returns (bool);

• Returns true if module matches the specified type
• Module types are defined as constants:
  • MODULE_TYPE_VALIDATOR = 1
  • MODULE_TYPE_EXECUTOR = 2
  • MODULE_TYPE_FALLBACK = 3
  • MODULE_TYPE_HOOK = 4

isInitialized

Checks if the module is initialized for a specific account.

function isInitialized(address smartAccount) external view returns (bool);

• Returns true if module is active for the account
• Used for validation before operations

Implementation Example

abstract contract BaseModule is IModule {
    // Tracks initialized accounts
    mapping(address => bool) internal initializedAccounts;

    function onInstall(bytes calldata data) external virtual {
        if (initializedAccounts[msg.sender]) {
            revert AlreadyInitialized(msg.sender);
        }
        initializedAccounts[msg.sender] = true;
        
        // Additional initialization logic
    }

    function onUninstall(bytes calldata data) external virtual {
        if (!initializedAccounts[msg.sender]) {
            revert NotInitialized(msg.sender);
        }
        initializedAccounts[msg.sender] = false;
        
        // Additional cleanup logic
    }

    function isInitialized(address smartAccount) public view virtual returns (bool) {
        return initializedAccounts[smartAccount];
    }
}

Best Practices

1. State Management

   • Use clear state variables for initialization tracking
   • Implement proper access control
   • Handle state changes atomically

2. Error Handling

   • Use custom errors for better gas efficiency
   • Include descriptive error messages
   • Validate all inputs

3. Gas Optimization

   • Use mappings for O(1) lookups
   • Minimize storage operations
   • Batch operations when possible

Security Considerations

1. Access Control

   • Only allow authorized accounts to install/uninstall
   • Validate caller permissions
   • Implement proper initialization checks

2. State Consistency

   • Ensure atomic state changes
   • Prevent reentrant calls
   • Validate state transitions

3. Upgrade Safety

   • Plan for potential upgrades
   • Maintain state consistency
   • Document state variables