Permission Management

Before diving into the technical aspect of permissions, we highly recommend that you first read the appropriate section.

In Mean Finance, the Permission Manager is the contract that handles everything related to permissions. It is actually pretty simple to use.

Checking if address has permissions

We have two different functions for checking permissions, hasPermission and hasPermissions. The first one is meant to check one permission, while the latter can be used to check many permissions in one call.

pragma solidity >=0.8.7 <0.9.0;

import '@mean-finance/dca-v2-core/contracts/interfaces/IDCAPermissionManager.sol';

contract MyContract {

    IDCAPermissionManager public immutable permissionManager;
    
    constructor(IDCAPermissionManager _permissionManager) {
        permissionManager = _permissionManager;
    }    
    
    /// @notice Returns whether the given address has the permission for the given token
    /// @param _id The id of the token to check
    /// @param _address The address of the user to check
    /// @param _permission The permission to check
    /// @return Whether the user has the permission or not
    function hasPermission(
        uint256 _id,
        address _address,
        Permission _permission
    ) external view returns (bool) {
        return permissionManager.hasPermission(_id, _address, _permission);
    }

    /// @notice Returns whether the given address has the permissions for the given token
    /// @param _id The id of the token to check
    /// @param _address The address of the user to check
    /// @param _permissions The permissions to check
    /// @return _hasPermissions Whether the user has each permission or not
    function hasPermissions(
        uint256 _id,
        address _address,
        Permission[] calldata _permissions
    ) external view returns (bool[] memory _hasPermissions) {
        return permissionManager.hasPermissions(_id, _address, _permissions);
    }

}

Setting/Deleting permissions

The Permission Manager has only one function that sets, modifies and deletes permissions, called modify. This function can set permissions for batch of operators, overwriting whatever permissions the operators had before. If you are looking to revoke all permissions from an operator, you'll need call modify and send an empty list of permissions.

Operators that are not sent to modify won't see their permissions affected in any way.

pragma solidity >=0.8.7 <0.9.0;

import '@mean-finance/dca-v2-core/contracts/interfaces/IDCAPermissionManager.sol';

contract MyContract {

    IDCAPermissionManager public immutable permissionManager;
    
    constructor(IDCAPermissionManager _permissionManager) {
        permissionManager = _permissionManager;
    }

    /// @notice Sets new permissions for the given tokens
    /// @dev Operators that are not part of the given permission sets do not see their permissions modified.
    /// In order to remove permissions to an operator, provide an empty list of permissions for them
    /// @param _id The token's id
    /// @param _permissions A list of permission sets
    function modify(uint256 _id, IDCAPermissionManager.PermissionSet[] calldata _permissions) external {
        permissionManager.modify(_id, _permissions);
    }    
}

Setting/Deleting permissions with permit

Finally, we've also added support for setting permissions by using a signature, similarly to EIP-2612.

pragma solidity >=0.8.7 <0.9.0;

import '@mean-finance/dca-v2-core/contracts/interfaces/IDCAPermissionManager.sol';

contract MyContract {

    IDCAPermissionManager public immutable permissionManager;
    
    constructor(IDCAPermissionManager _permissionManager) {
        permissionManager = _permissionManager;
    }

    /// @notice Sets permissions via signature
    /// @dev This method works similarly to `modify`, but instead of being executed by the owner, it can be set my signature
    /// @param _permissions The permissions to set
    /// @param _tokenId The token's id
    /// @param _deadline The deadline timestamp by which the call must be mined for the approve to work
    /// @param _v Must produce valid secp256k1 signature from the holder along with `r` and `s`
    /// @param _r Must produce valid secp256k1 signature from the holder along with `v` and `s`
    /// @param _s Must produce valid secp256k1 signature from the holder along with `r` and `v`
    function permissionPermit(
        IDCAPermissionManager.PermissionSet[] calldata _permissions,
        uint256 _tokenId,
        uint256 _deadline,
        uint8 _v,
        bytes32 _r,
        bytes32 _s
    ) external {
        permissionManager.permissionPermit(_permissions, _tokenId, _deadline, _v, _r, _s);
    }
}