StakingVault Contract

ERC4626 vault with voting power, multi-token rewards, and configurable unstaking delays

Overview

The StakingVault contract is a transferrable ERC4626 vault that enables staking of an underlying token to earn voting power and multi-token rewards. It implements the full ERC20Votes interface for governance participation and supports configurable unstaking delays for security.

Key Features

• ERC4626 Standard: Full compatibility with vault standards
• ERC20Votes: Voting power delegation for governance
• Multi-Token Rewards: Support for unlimited reward tokens with drip distribution
• Unstaking Delay: Configurable delay for withdrawals
• Exponential Reward Decay: Smooth reward distribution using half-life model
• Slashing Mechanism: Ability to burn shares for punitive actions

Architecture

StakingVault extends:

• ERC4626Upgradeable (vault functionality)
• ERC20PermitUpgradeable (gasless approvals)
• ERC20VotesUpgradeable (governance)
• OwnableUpgradeable (access control)
• UUPSUpgradeable (upgradeability)

Staking Functions

Deposit and Delegate

Deposit tokens and automatically self-delegate voting power.

assets · uint256

Amount of underlying tokens to deposit

StakingVault.sol

function depositAndDelegate(uint256 assets) external returns (uint256 shares)

This convenience function combines deposit() and delegate() into a single transaction, automatically delegating voting power to yourself.

Burn (Slashing)

Burn shares and redistribute underlying tokens to remaining holders.

_shares · uint256

Amount of shares to burn

StakingVault.sol

function burn(uint256 _shares) external

This is a slashing function. Burned shares reduce the caller’s balance and automatically distribute the underlying assets to all remaining stakers as native rewards.

Unstaking Configuration

Set Unstaking Delay

Configure the delay before withdrawn tokens become claimable.

_delay · uint256

New unstaking delay in seconds (max 4 weeks)

StakingVault.sol

function setUnstakingDelay(uint256 _delay) external onlyOwner

MAX_UNSTAKING_DELAY · uint256 · default: "4 weeks"

Maximum allowed unstaking delay

Reward Management

Add Reward Token

Add a new reward token to the vault.

_rewardToken · address

Address of the reward token to add

StakingVault.sol

function addRewardToken(address _rewardToken) external onlyOwner

Reward tokens cannot be the vault’s share token or underlying asset. The contract tracks the token’s balance and distributes new tokens using an exponential decay curve.

Remove Reward Token

Remove a reward token from future distributions.

_rewardToken · address

Address of the reward token to remove

StakingVault.sol

function removeRewardToken(address _rewardToken) external onlyOwner

Users can still claim accrued rewards for removed tokens. This only stops new rewards from accumulating.

Claim Rewards

Claim accumulated rewards for specified tokens.

_rewardTokens · address[]

Array of reward token addresses to claim

StakingVault.sol

function claimRewards(
    address[] calldata _rewardTokens
) external returns (uint256[] memory claimableRewards)

Set Reward Ratio

Configure the reward distribution rate via half-life.

rewardHalfLife · uint256

Half-life for reward handout in seconds (1 day to 2 weeks)

StakingVault.sol

function setRewardRatio(uint256 rewardHalfLife) external onlyOwner

MAX_REWARD_HALF_LIFE · uint256 · default: "2 weeks"

Maximum reward half-life

MIN_REWARD_HALF_LIFE · uint256 · default: "1 day"

Minimum reward half-life

View Functions

Get All Reward Tokens

Retrieve all currently registered reward tokens.

StakingVault.sol

function getAllRewardTokens() external view returns (address[] memory)

Total Assets

Get total underlying assets including accrued native rewards.

StakingVault.sol

function totalAssets() public view override returns (uint256)

Poke

Manually trigger reward accrual for the caller.

StakingVault.sol

function poke() external

This function is useful for updating your reward balances without performing a deposit or withdrawal.

Reward Tracking Structures

RewardInfo

payoutLastPaid · uint256

Timestamp of last reward calculation

rewardIndex · uint256

Cumulative reward per share (D18+decimals)

balanceAccounted · uint256

Amount of rewards already distributed to index

balanceLastKnown · uint256

Last known total balance of reward token

totalClaimed · uint256

Total amount claimed by all users

UserRewardInfo

lastRewardIndex · uint256

User’s last checkpoint reward index

accruedRewards · uint256

Unclaimed rewards for this user

Events

UnstakingDelaySet · event

Emitted when unstaking delay is updated

Parameters:

• delay - New unstaking delay in seconds

RewardTokenAdded · event

Emitted when a reward token is registered

Parameters:

• rewardToken - Address of the added reward token

RewardTokenRemoved · event

Emitted when a reward token is removed

Parameters:

• rewardToken - Address of the removed reward token

RewardsClaimed · event

Emitted when a user claims rewards

Parameters:

• user - Address claiming rewards
• rewardToken - Token being claimed
• amount - Amount claimed

RewardRatioSet · event

Emitted when reward distribution rate changes

Parameters:

• rewardRatio - New reward ratio (per-second rate)
• halfLife - Corresponding half-life in seconds

Unstaking Manager

When unstaking delay is non-zero, withdrawals are managed by a separate UnstakingManager contract:

unstakingManager · UnstakingManager

Automatically deployed contract that holds tokens during unstaking period

Users receive a lock ID when unstaking and must wait for the delay period before calling claimLock() on the UnstakingManager.

Usage Example

// Deposit and start earning rewards
uint256 shares = vault.depositAndDelegate(1000e18);

// Wait for rewards to accumulate
// ...

// Claim rewards
address[] memory tokens = vault.getAllRewardTokens();
uint256[] memory claimed = vault.claimRewards(tokens);

// Initiate withdrawal (creates lock if delay > 0)
vault.withdraw(shares, receiver, owner);

// After delay, claim from UnstakingManager
vault.unstakingManager().claimLock(lockId);

Constants

SCALAR · uint256 · default: "1e18"

Scaling factor for reward calculations

LN_2 · uint256 · default: "0.693147180559945309e18"

Natural logarithm of 2 (for exponential decay)