MezzHub

Git Source

Inherits: CommonValidation, ModifiedOwnable2StepUpgradeable, DelayedUUPSUpgradeable, IMezzHub

Author: Daniel Yamagata & Jerry Qi & Naveen Ailawadi

The central contract of the Mezzanine protocol. It manages the protocol state and whitelists and is used by 'core' contracts to query 'non-core' contracts

The addresses of the 'non-core' contracts can only be updated via an upgrade, which must be proposed and executed by the 'owner'. Upgrades require a delay before they can be executed. Similarly, the transfer of ownership requires a delay before it can be accepted. The renouncement of ownership is disabled to prevent griefing by a compromised 'owner'. The re-enablement of this functionality must be done via an upgrade

State Variables

PRECISION_FACTOR

uint256 public constant PRECISION_FACTOR = Constants.PRECISION_FACTOR;

MezzHubStorageLocation

bytes32 private constant MezzHubStorageLocation = 0x3de7a073c0cce790cf3a28a9e9c6ae84d1b91b340e346453198ee61a13723200;

Functions

_getMezzHubStorage

function _getMezzHubStorage() internal pure returns (MezzHubStorage storage $);

constructor

constructor();

onlyOwnerOrDefender

Reverts if the caller is not the 'owner' or a 'defender'

modifier onlyOwnerOrDefender();

ownershipTransferSnapshot

Returns the snapshot of the ownership transfer. This snapshot must pass before a pending ownership transfer can occur. If there is no pending ownership transfer, this will will return zero

function ownershipTransferSnapshot() public view returns (uint256);

frozenSnapshot

Returns the snapshot of the protocol freeze. This snapshot must pass before the protocol can

function frozenSnapshot() public view returns (uint256);

owner

Returns the address of the Mezz Hub owner

function owner() public view virtual override(IMezzHub, OwnableUpgradeable) returns (address);

init

Initializes the Mezz Hub state. Can only be called once

function init(address initOwner, address initDocumentRegistry, address initMezzDeployer, address initFeeController)
    external
    initializer;

Parameters

Name	Type	Description
initOwner	address	The address of the initial Mezz Hub owner
initDocumentRegistry	address	The address of the Document Registry
initMezzDeployer	address	The address of the Mezz Deployer
initFeeController	address	The address of the Fee Controller

__MezzHub_init

function __MezzHub_init(address initDocumentRegistry, address initMezzDeployer, address initFeeController)
    internal
    onlyInitializing;

transferOwnership

Overridden 'transferOwnership' such that a snapshot is taken upon the transfer of ownership

function transferOwnership(address newOwner) public virtual override;

acceptOwnership

Overridden '_acceptOwnership' such that the snapshot is validated before the ownership transfer is accepted

function acceptOwnership() public virtual override;

cancelOwnershipTransfer

Cancels a pending ownership transfer. Only callable by the 'owner' or a 'defender' Deletes the snapshot of the ownership transfer and the pending owner

function cancelOwnershipTransfer() public virtual onlyOwnerOrDefender;

renounceOwnership

Deprecation of 'renounceOwnership' from OwnableUpgradeable to prevent griefing by a compromised 'owner'

function renounceOwnership() public virtual override;

freezeProtocol

Freezes the protocol for 'freezeDuration', which can be up to 14 days. Only callable by the 'owner' or a 'defender' The protocol can be re-frozen at any point while it is frozen.

function freezeProtocol(uint48 freezeDuration) external onlyOwnerOrDefender;

Parameters

Name	Type	Description
freezeDuration	uint48	The duration to freeze the protocol for in seconds

setProtocolState

Sets the protocol state. Only callabe by the owner.

Protocol state is defined by the following enum:

• 0: Active

• 1: Paused

• 2: Frozen

If protocol state is set by this function, it will be permanently set until this function is called again to change state.

function setProtocolState(DataTypes.ProtocolState newState) external override onlyOwner;

Parameters

Name	Type	Description
newState	DataTypes.ProtocolState	The protocol state to set

proposeUpgrade

Proposes an upgrade to the contract's implementation

The caller must be authorized to propose an upgrade. This authorization is determined by inheriting contracts

function proposeUpgrade(address newImplementation) external override onlyOwner returns (uint256);

Parameters

Name	Type	Description
newImplementation	address	The address of the new implementation

Returns

Name	Type	Description
<none>	uint256	The snapshot of the pending upgrade as a unix-timestamp

cancelProposedUpgrade

Cancels the pending upgrade, deleting the 'pendingUpgrade' and 'pendingUpgradeSnapshot' in storage

The caller must be authorized to cancel a pending upgrade. This authorization is determined by inheriting contracts

function cancelProposedUpgrade() external override onlyOwnerOrDefender;

setFrozenImplementation

Sets the 'implementationToSet' to 'setting'. If true and 'implementationToSet' is StateAware, the implementation's pausable and freezable functions will revert Only callable by the 'owner'

function setFrozenImplementation(address implementationToSet, bool setting) external onlyOwner;

setFrozenDeployment

Sets the 'deploymentToSet' to 'setting'. If true, the deployment's pausable and freezable functions will revert Only callable by the 'owner' or a 'defender'

function setFrozenDeployment(address deploymentToSet, bool setting) external onlyOwnerOrDefender;

addWhitelistedDenominationAsset

Adds 'denominationAssetToAdd' to the denomination asset whitelist. Only callable by the 'owner'

The owner should be cautious to never add ERC777s to the whitelist to prevent possible reentrancy attacks

function addWhitelistedDenominationAsset(address denominationAssetToAdd) external onlyOwner;

removeWhitelistedDenominationAsset

Removes 'denominationAssetToRemove' from the denomination asset whitelist. Only callable by the 'owner'

function removeWhitelistedDenominationAsset(address denominationAssetToRemove) external onlyOwner;

addDefender

Adds 'defenderToAdd' to the set of defenders. Only callable by the 'owner'

function addDefender(address defenderToAdd) external onlyOwner;

removeDefender

Removes 'defenderToRemove' from the set of defenders. Only callable by the 'owner'

function removeDefender(address defenderToRemove) external onlyOwner;

isDefender

Returns true if 'defenderToCheck' is a defender, false otherwise

function isDefender(address defenderToCheck) external view returns (bool);

isDenominationAsset

Returns true 'denominationAssetToCheck' is whitelisted, false otherwise

function isDenominationAsset(address denominationAssetToCheck) external view returns (bool);

isDeploymentFrozen

Returns true if 'deploymentToCheck' is frozen, false otherwise

function isDeploymentFrozen(address deploymentToCheck) external view returns (bool);

isImplementationFrozen

Returns true if 'implementationToCheck' is frozen, false otherwise

function isImplementationFrozen(address implementationToCheck) external view returns (bool);

getDefenders

Returns the set of defenders as an array of addresses

function getDefenders() external view returns (address[] memory);

getDenominationAssets

Returns the set of denomination assets in no specific order

function getDenominationAssets() external view returns (address[] memory);

getDocumentRegistry

Returns the address of the Document Registry

Used by core contracts

function getDocumentRegistry() external view returns (address);

getFeeController

Returns the address of the fee controller

Used by core contracts

function getFeeController() external view returns (address);

getMezzDeployer

Returns the address of the Mezz Deployer

Used by the core contracts

function getMezzDeployer() external view returns (address);

getProtocolState

Returns the Protocol State as an enum, DataTypes.ProtocolState

*The protocol state is defined by the following enum:

• 0: Active

• 1: Paused

• 2: Frozen

The protocol can be frozen in two ways:

• (1) The protocol's state was set to 'Frozen' by the owner via 'setProtocolState()'. If this is the case, it can be unfrozen at any point in time

• (2) The 'owner' or a 'defender' set the protocol's state to 'Frozen' via 'freezeProtocol()', which freezes the protocol for a period of time. It cannot be unfrozen until this time passes*

function getProtocolState() external view returns (DataTypes.ProtocolState);

_setDocumentRegistry

function _setDocumentRegistry(address newDocumentRegistry) internal;

_setMezzDeployer

function _setMezzDeployer(address newMezzDeployer) internal;

_setFeeController

function _setFeeController(address newFeeController) internal;

_validateCallerIsOwnerOrDefender

Reverts if the caller is not the 'owner' or a 'defender'

function _validateCallerIsOwnerOrDefender() internal view;

_isCallerDefender

function _isCallerDefender() internal view returns (bool);

_isCallerOwner

function _isCallerOwner() internal view returns (bool);

_authorizeUpgrade

Overridden '_authorizeUpgrade()' from DelayedUUPSUpgradeable such that only the 'owner' can execute an upgrade

function _authorizeUpgrade(address newImplementation) internal view override onlyOwner;

Structs

MezzHubStorage

struct MezzHubStorage {
    address _documentRegistry;
    uint96 _ownershipTransferSnapshot;
    address _mezzDeployer;
    address _feeController;
    DataTypes.ProtocolState _protocolState;
    uint48 _frozenSnapshot;
    EnumerableSet.AddressSet _defenders;
    EnumerableSet.AddressSet _denominationAssetWhitelist;
    mapping(address => bool) _frozenImplementations;
    mapping(address => bool) _frozenDeployments;
}