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core staking contracts

PriorityPool Contract: Staking Queue and Liquidity Buffer

The PriorityPool allows users to queue asset tokens which are eventually deposited into a StakingPool when deposit room becomes available. The liquid staking tokens (LSTs) minted by the StakingPool are then distributed using a merkle tree.

Each user will continuously receive LSTs as more deposits are made into the StakingPool until they have received an amount equal to the amount of asset tokens they deposited into the PriorityPool. The rate at which each user receives LSTs is dependent on the user’s reSDL balance in the SDLPool. A higher reSDL balance entitles the user to receive LSTs at a faster rate than a user with a smaller reSDL balance. Users that hold no reSDL can also deposit into the PriorityPool but they will receive no LSTs as long as there are users with deposits in the PriorityPool that also hold reSDL.

The secondary function of the PriorityPool is to act as a liquidity buffer for the StakingPool it deposits into. When a user redeems LSTs for the underlying asset token, these LSTs will be swapped with queued asset tokens from the PriorityPool if possible before queuing tokens in the WithdrawalPool. This both reduces gas costs for the user and ensures that the StakingPool earns the most yield possible as yield earning asset tokens remain in the pool instead of being withdrawn.

View Functions

Section titled “View Functions”

token

Section titled “token”

Returns the address of the token this pool handles

function token() external view returns (address)

Return Values

Section titled “Return Values”
Name Type Description
token address address of token

stakingPool

Section titled “stakingPool”

Returns the address of the staking pool that this pool deposits into

function stakingPool() external view returns (address)

Return Values

Section titled “Return Values”
Name Type Description
stakingPool address address of staking pool

sdlPool

Section titled “sdlPool”

Returns the address of the SDL pool

function sdlPool() external view returns (address)

Return Values

Section titled “Return Values”
Name Type Description
sdlPool address address of SDL pool

distributionOracle

Section titled “distributionOracle”

Returns the address of the oracle that handles distribution of liquid staking tokens

function distributionOracle() external view returns (address)

Return Values

Section titled “Return Values”
Name Type Description
distributionOracle address address of distribution oracle

rebaseController

Section titled “rebaseController”

Returns the address of the rebase controller

function rebaseController() external view returns (address)

Return Values

Section titled “Return Values”
Name Type Description
rebaseController address address of rebase controller

withdrawalPool

Section titled “withdrawalPool”

Returns the address of the withdrawal pool

function withdrawalPool() external view returns (address)

Return Values

Section titled “Return Values”
Name Type Description
withdrawalPool address address of withdrawal pool

queueDepositMin

Section titled “queueDepositMin”

Returns the minimum amount of tokens required to execute a deposit

function queueDepositMin() external view returns (uint256)

Return Values

Section titled “Return Values”
Name Type Description
depositMin uint256 queue deposit minimum

queueDepositMax

Section titled “queueDepositMax”

Returns the maximum amount of tokens that can be deposited in a single deposit

function queueDepositMax() external view returns (uint256)

Return Values

Section titled “Return Values”
Name Type Description
depositMax uint256 queue deposit maximum

poolStatus

Section titled “poolStatus”

Returns the current status of the pool

0 - OPEN (nothing disabled)
1 - DRAINING (deposits disabled)
2 - CLOSED (deposits/withdrawals disabled)

function poolStatus() external view returns (PoolStatus)

Return Values

Section titled “Return Values”
Name Type Description
poolStatus PoolStatus current status of the pool

merkleRoot

Section titled “merkleRoot”

Returns the merkle root for the latest distribution tree

function merkleRoot() external view returns (bytes32)

Return Values

Section titled “Return Values”
Name Type Description
merkleRoot bytes32 current merkle root

ipfsHash

Section titled “ipfsHash”

Returns the ipfs hash of the balance data for the latest distribution tree

function ipfsHash() external view returns (bytes32)

Return Values

Section titled “Return Values”
Name Type Description
ipfsHash bytes32 current ipfsHash

merkleTreeSize

Section titled “merkleTreeSize”

Returns the number of unique addresses contained in the latest distribution tree

function merkleTreeSize() external view returns (uint256)

Return Values

Section titled “Return Values”
Name Type Description
merkleTreeSize uint256 current merkle tree size

totalQueued

Section titled “totalQueued”

Returns the total amount of token deposits in the pool waiting to be deposited into the staking pool

function totalQueued() external view returns (uint256)

Return Values

Section titled “Return Values”
Name Type Description
totalQueued uint256 total deposits in the pool

getAccounts

Section titled “getAccounts”

Returns a list of all accounts that have deposited into the pool in the order that they appear in the distribution tree

function getAccounts() external view returns (address[])

Return Values

Section titled “Return Values”
Name Type Description
accounts address[] list of accounts

getAccountIndex

Section titled “getAccountIndex”

Returns the index of an account representing it’s position in the distribution tree

function getAccountIndex(address _account) external view returns (uint256)

Parameters

Section titled “Parameters”
Name Type Description
_account address account address

Return Values

Section titled “Return Values”
Name Type Description
index uint256 account index

getQueuedTokens

Section titled “getQueuedTokens”

Returns an account’s current amount of deposits in the pool (_distributionAmount is stored on IPFS)

function getQueuedTokens(address _account, uint256 _distributionAmount) public view returns (uint256)

Parameters

Section titled “Parameters”
Name Type Description
_account address account address
_distributionAmount uint256 account’s distribution amount from the latest distribution tree

Return Values

Section titled “Return Values”
Name Type Description
queuedTokens uint256 amount of queued tokens for account

getLSDTokens

Section titled “getLSDTokens”

Returns an account’s current amount of withdrawable liquid staking tokens (_distributionShareAmount is stored on IPFS)

function getLSDTokens(address _account, uint256 _distributionShareAmount) external view returns (uint256)

Parameters

Section titled “Parameters”
Name Type Description
_account address account address
_distributionShareAmount uint256 account’s distribution share amounts from the latest distribution tree

Return Values

Section titled “Return Values”
Name Type Description
lsdTokens uint256 withdrawable LSD tokens for account

getLSDTokensBatch

Section titled “getLSDTokensBatch”

Returns the current amount of withdrawable LSD tokens for multiple accounts.

function getLSDTokensBatch(address[] calldata _accounts, uint256[] calldata _distributionShareAmounts) external view returns (uint256[] memory)

Parameters

Section titled “Parameters”
Name Type Description
_accounts address[] List of account addresses
_distributionShareAmounts uint256[] Distribution share amounts for each account

Return Values

Section titled “Return Values”
Name Type Description
lsdTokens uint256[] Withdrawable LSD tokens for accounts

canWithdraw

Section titled “canWithdraw”

Returns the total amount of asset tokens that an account can withdraw (includes account’s queued tokens and stLINK balance and takes into account both priority pool and staking pool liquidity)

function canWithdraw(address _account, uint256 _distributionAmount) external view returns (uint256)

Parameters

Section titled “Parameters”
Name Type Description
_account address account address
_distributionAmount uint256 account’s distribution amount from the latest distribution tree

Return Values

Section titled “Return Values”
Name Type Description
canWithdraw uint256 amount of withdrawable tokens

checkUpkeep

Section titled “checkUpkeep”

Returns whether a call should be made to performUpkeep to deposit queued/unused tokens
into staking pool strategies

function checkUpkeep(bytes) external view returns (bool, bytes)

Return Values

Section titled “Return Values”
Name Type Description
upkeepNeeded bool whether a call should be made to performUpkeep
upkeepNeeded bytes encoded amount of tokens to be deposited

getDepositsSinceLastUpdate

Section titled “getDepositsSinceLastUpdate”

Returns the amount of new deposits into the staking pool since the last call to updateDistribution and the amount of shares received for those deposits

function getDepositsSinceLastUpdate() external view returns (uint256, uint256)

Return Values

Section titled “Return Values”
Name Type Description
deposits uint256 amount of deposits
shares uint256 amount of shares

getAccountData

Section titled “getAccountData”

Returns account data used for calculating a new merkle tree

A new merkle tree is calculated based on users’ reSDL balance and the number of tokens they have queuedAccounts are returned in the same order as they are in the merkle tree

function getAccountData() external view returns (address[], uint256[], uint256[])

Return Values

Section titled “Return Values”
Name Type Description
accounts address[] list of all accounts that have ever queued tokens
sdlBalances uint256[] list of SDL balances for each account
queuedBalances uint256[] list of queued token amounts for each account (ignores distributed LSD tokens)

Write Functions

Section titled “Write Functions”

onTokenTransfer

Section titled “onTokenTransfer”

ERC677 implementation to receive a token deposit or withdrawal

Can receive both asset tokens (deposit) and liquid staking tokens (withdrawal)

function onTokenTransfer(address _sender, uint256 _value, bytes _calldata) external

Parameters

Section titled “Parameters”
Name Type Description
_sender address sender of the transfer
_value uint256 value of the transfer
_calldata bytes encoded shouldQueue (bool) and deposit data to pass to staking pool strategies (bytes[])

deposit

Section titled “deposit”

Deposits asset tokens into the staking pool and/or queues them

function deposit(uint256 _amount, bool _shouldQueue, bytes _data) external

Parameters

Section titled “Parameters”
Name Type Description
_amount uint256 amount to deposit
_shouldQueue bool whether tokens should be queued if there’s no room in the staking pool
_data bytes deposit data passed to staking pool strategies

withdraw

Section titled “withdraw”

Withdraws asset tokens

Will unqueue sender’s asset tokens before swapping liquid staking tokens if there is sufficient liquidity and _shouldUnqueue is set to true

function withdraw(uint256 _amountToWithdraw, uint256 _amount, uint256 _sharesAmount, bytes32[] _merkleProof, bool _shouldUnqueue, bool _shouldUnqueueWithdrawal) external

Parameters

Section titled “Parameters”
Name Type Description
_amountToWithdraw uint256 amount of tokens to withdraw
_amount uint256 amount as recorded in sender’s merkle tree (stored on IPFS)entry
_sharesAmount uint256 shares amount as recorded in sender’s merkle tree (stored on IPFS)entry
_merkleProof bytes32[] merkle proof for sender’s merkle tree entry (generated from IPFS data)
_shouldUnqueue bool whether tokens should be unqueued before taking LSD tokens
_shouldQueueWithdrawal bool whether a withdrawal should be queued if the full withdrawal amount cannot be satisfied

unqueueTokens

Section titled “unqueueTokens”

Withdraws queued deposits from the priority pool

function unqueueTokens(uint256 _amountToUnqueue, uint256 _amount, uint256 _sharesAmount, bytes32[] _merkleProof) external

Parameters

Section titled “Parameters”
Name Type Description
_amountToUnqueue uint256 amount of tokens to unqueue
_amount uint256 amount as recorded in sender’s merkle tree entry (stored on IPFS)
_sharesAmount uint256 shares amount as recorded in sender’s merkle tree entry (stored on IPFS)
_merkleProof bytes32[] merkle proof for sender’s merkle tree entry (generated from IPFS data)

claimLSDTokens

Section titled “claimLSDTokens”

Claims withdrawable liquid staking tokens

function claimLSDTokens(uint256 _amount, uint256 _sharesAmount, bytes32[] _merkleProof) external

Parameters

Section titled “Parameters”
Name Type Description
_amount uint256 amount as recorded in sender’s merkle tree entry
_sharesAmount uint256 shares amount as recorded in sender’s merkle tree entry
_merkleProof bytes32[] merkle proof for sender’s merkle tree entry

depositQueuedTokens

Section titled “depositQueuedTokens”

Deposits queued tokens and/or unused tokens sitting in staking pool

function depositQueuedTokens(uint256 _queueDepositMin, uint256 _queueDepositMax, bytes[] _data) external

Parameters

Section titled “Parameters”
Name Type Description
_queueDepositMin uint256 min amount of tokens required for deposit into staking pool strategies
_queueDepositMax uint256 max amount of tokens that can be deposited into staking pool strategies at once
_data bytes[] list of deposit data passed to staking pool strategies

performUpkeep

Section titled “performUpkeep”

Deposits queued and/or unused tokens

function performUpkeep(bytes _performData) external

Parameters

Section titled “Parameters”
Name Type Description
_performData bytes[] encoded list of deposit data to be passed to staking pool strategies (bytes[])

updateDistribution

Section titled “updateDistribution”

Distributes a new batch of liquid staking tokens to users that have queued deposits

function updateDistribution(bytes32 _merkleRoot, bytes32 _ipfsHash, uint256 _amountDistributed, uint256 _sharesAmountDistributed) external

Parameters

Section titled “Parameters”
Name Type Description
_merkleRoot bytes32 new merkle root for the distribution tree
_ipfsHash bytes32 new ipfs hash for the distribution tree (CIDv0, no prefix - only hash)
_amountDistributed uint256 amount of LSD tokens distributed in this distribution
_sharesAmountDistributed uint256 amount of LSD shares distributed in this distribution

executeQueuedWithdrawals

Section titled “executeQueuedWithdrawals”

Executes a batch of withdrawals that have been queued in the withdrawal pool

Withdraws tokens from the staking pool and sends them to the withdrawal pool

 function executeQueuedWithdrawals(uint256 _amount, bytes[] _data) external

Parameters

Section titled “Parameters”
Name Type Description
_amount uint256 total amount to withdraw
_data bytes list of withdrawal data passed to staking pool strategies

pauseForUpdate

Section titled “pauseForUpdate”

Pauses queueing and unqueueing so a new merkle tree can be generated

function pauseForUpdate() external

setPoolStatus

Section titled “setPoolStatus”

Sets the pool’s status

function setPoolStatus(enum PriorityPool.PoolStatus _status) external

Parameters

Section titled “Parameters”
Name Type Description
_status PoolStatus pool status

setQueueDepositParams

Section titled “setQueueDepositParams”

Sets the minimum and maximum amount that can be deposited into strategies at once

function setQueueDepositParams(uint128 _queueDepositMin, uint128 _queueDepositMax) external

Parameters

Section titled “Parameters”
Name Type Description
_queueDepositMin uint128 minimum amount of tokens required for deposit into staking pool strategies
_queueDepositMax uint128 maximum amount of tokens that can be deposited into staking pool strategies at once

setDistributionOracle

Section titled “setDistributionOracle”

Sets the distribution oracle

function setDistributionOracle(address _distributionOracle) external

Parameters

Section titled “Parameters”
Name Type Description
_distributionOracle address address of oracle

setRebaseController

Section titled “setRebaseController”

Sets the rebase controller

This address has authorization to close the pool in case of emergency

function setRebaseController(address _rebaseController_) external

Parameters

Section titled “Parameters”
Name Type Description
_rebaseController address address of rebase controller

setWithdrawalPool

Section titled “setWithdrawalPool”

Sets the withdrawal pool

function setWithdrawalPool(address _withdrawalPool) external

Parameters

Section titled “Parameters”
Name Type Description
_withdrawalPool address address of withdrawal pool

setAllowInstantWithdrawals

Section titled “setAllowInstantWithdrawals”

Sets whether instant withdrawals are enabled.

function setAllowInstantWithdrawals(bool _allowInstantWithdrawals) external

Parameters

Section titled “Parameters”
Name Type Description
_allowInstantWithdrawals bool Whether instant withdrawals enabled

allowInstantWithdrawals

Section titled “allowInstantWithdrawals”

Returns whether instant withdrawals are enabled.

function allowInstantWithdrawals() external view returns (bool)

Return Values

Section titled “Return Values”
Name Type Description
allowInstantWithdrawals bool Whether instant withdrawals enabled