SwapPool

Swap pool contract. May or may not be covered by a backstop pool. Conceptionally, there are two ways to temporarily disable a pool: The owner can either pause the pool, disabling deposits, swaps & backstop, or the owner can set the pool cap to zero which only prevents deposits. The former is for security incidents, the latter for phasing out a pool.

SwapFees

struct SwapFees {
  uint32 lpFee;
  uint32 backstopFee;
  uint32 protocolFee;
}

totalLiabilities

uint256 totalLiabilities

The liabilities of the pool Cannot just use totalSupply() as the totalLiabilities will accumulate also the LP fees from swaps. This is fixed point number using the decimals of this pool

reserve

uint256 reserve

The amount of pool tokens usable for swaps This is fixed point number using the decimals of this pool

reserveWithSlippage

uint256 reserveWithSlippage

The amount of pool tokens plus the slippage The relationship with reserve is: reserveWithSlippage = slippageCurve.psi(reserve, totalLiabilities) However this relationship will never hold precisely and will deviate slightly for numerical reasons!! All code needs to work even if this relationship does not hold This is fixed point number using the decimals of this pool

maxCoverageRatioForSwapIn

uint256 maxCoverageRatioForSwapIn

safeRedeemPercentage

uint256 safeRedeemPercentage

safeRedeemInterval

uint256 safeRedeemInterval

lastBackstopBurnTimestamp

uint256 lastBackstopBurnTimestamp

lastAvailableAmountForSafeRedeem

uint256 lastAvailableAmountForSafeRedeem

protocolTreasury

address protocolTreasury

lastDepositAt

mapping(address => uint256) lastDepositAt

lastDepositAmount

mapping(address => uint256) lastDepositAmount

backstop

contract IBackstopPool backstop

router

contract IRouter router

router instance for this swap pool

slippageCurve

contract ISlippageCurve slippageCurve

deposit

function deposit(uint256 _depositAmount, uint256 _minLPAmountOut, uint256 _deadline) external returns (uint256 sharesToMint_, int256 fee_)

Deposits amount of tokens into pool Will change cov ratio of pool, will increase delta to 0

Parameters

Name
Type
Description

_depositAmount

uint256

The amount to be deposited, an amount of pool tokens

_minLPAmountOut

uint256

Minimum amount of pool lp tokens to mint

_deadline

uint256

Unix timestamp after which the transaction will revert

Return Values

Name
Type
Description

sharesToMint_

uint256

Total number of pool lp tokens minted

fee_

int256

The slippage reward (a negative fee), fixed point number using the pool decimals

quoteDeposit

function quoteDeposit(uint256 _depositAmount) external view returns (uint256 sharesToMint_, uint256 slippageReward_)

Get a quote for the effective amount of tokens for a deposit

Parameters

Name
Type
Description

_depositAmount

uint256

The amount to be deposited

Return Values

Name
Type
Description

sharesToMint_

uint256

Total number of pool LP tokens to be minted (incl. slippage)

slippageReward_

uint256

The reward due to slippage, fixed point number using the pool decimals

withdraw

function withdraw(uint256 _sharesToBurn, uint256 _minimumAmount, uint256 _deadline) external returns (uint256 payoutAmount_, int256 fee_)

Withdraws liquidity amount of asset ensuring minimum amount required

Parameters

Name
Type
Description

_sharesToBurn

uint256

The liquidity to be withdrawn, an amount of LP tokens

_minimumAmount

uint256

The minimum amount of returned pool tokens that will be accepted by user

_deadline

uint256

Unix timestamp after which the transaction will revert

Return Values

Name
Type
Description

payoutAmount_

uint256

Amount of pool tokens withdrawn after applying withdrawal fee

fee_

int256

The penalty due to slippage (a positive fee), fixed point number using the pool decimals

quoteWithdraw

function quoteWithdraw(uint256 _sharesToBurn) external view returns (uint256 payoutAmount_, uint256 slippagePenalty_)

Get a quote for the effective amount of tokens for a withdrawal

Parameters

Name
Type
Description

_sharesToBurn

uint256

Total number of pool LP tokens to be burned

Return Values

Name
Type
Description

payoutAmount_

uint256

The amount to be withdrawn (incl. slippage)

slippagePenalty_

uint256

The penalty due to slippage

backstopBurn

function backstopBurn(address _owner, uint256 _sharesToBurn) external returns (uint256 amount_)

Burns swap pool LP tokens of owner, will get compensated using backstop liquidity (reedem swap pool shares) Can only be invoked by backstop pool, disabled when pool is paused

Parameters

Name
Type
Description

_owner

address

The LP's address whose LP tokens should be burned

_sharesToBurn

uint256

The number of LP tokens of this pool to burn

Return Values

Name
Type
Description

amount_

uint256

The amount of asset() tokens that the burned shares were worth

getMaxRedeemSwapPoolShares

function getMaxRedeemSwapPoolShares() external view returns (uint256 maxShares_)

Get the maximum amount of swap pool LP tokens that can be burned (CR <= 100%)

Return Values

Name
Type
Description

maxShares_

uint256

The maximum amount of LP tokens that can be burned

backstopDrain

function backstopDrain(uint256 _amount, address _recipient) external returns (uint256 swapAmount_)

For backstop pool to withdraw liquidity if swap pool's coverage ratio > 100% Can only be invoked by backstop pool

Parameters

Name
Type
Description

_amount

uint256

The amount of asset() tokens to be moved out of swap pool

_recipient

address

Address to send the funds to

Return Values

Name
Type
Description

swapAmount_

uint256

The amount of asset() tokens that are transfered to _recipient

quoteBackstopDrain

function quoteBackstopDrain(uint256 _amount) external view returns (uint256 swapAmount_)

Get a quote for the effective amount of tokens for a backstop drain

Parameters

Name
Type
Description

_amount

uint256

The amount of tokens to be withdrawn for backstop liquidity

Return Values

Name
Type
Description

swapAmount_

uint256

The amount to be withdrawn (incl. slippage)

quoteSwapInto

function quoteSwapInto(uint256 _amount) public view returns (uint256 effectiveAmount_)

Get a quote for the effective amount of tokens for a swap into

Parameters

Name
Type
Description

_amount

uint256

The amount of pool tokens to swap into the pool

Return Values

Name
Type
Description

effectiveAmount_

uint256

Effective amount, incl. slippage (penalty or rewards)

quoteSwapOut

function quoteSwapOut(uint256 _amount) public view returns (uint256 effectiveAmount_, uint256 protocolFeeWithSlippage_, uint256 effectiveLpFee_, uint256 backstopFee_)

Get a quote for the effective amount of tokens, incl. slippage and fees

Parameters

Name
Type
Description

_amount

uint256

The amount of pool asset to swap out of the pool

Return Values

Name
Type
Description

effectiveAmount_

uint256

Effective amount, incl. slippage and fees

protocolFeeWithSlippage_

uint256

The protocol fee that is to be sent to the treasury

effectiveLpFee_

uint256

The actual LP fee – totalLiabilities should be incremented by this value

backstopFee_

uint256

The effective backstop fee

coverage

function coverage() external view returns (uint256 reserves_, uint256 liabilities_)

returns pool coverage ratio

Return Values

Name
Type
Description

reserves_

uint256

Current amount of usable asset() tokens (without slippage)

liabilities_

uint256

total amount of asset deposited by liquidity providers

getExcessLiquidity

function getExcessLiquidity() external view returns (int256 excessLiquidity_)

Computes the excess liquidity that forms that valuation of the backstop pool is defined as b + C - B - L where

  • b is reserve

  • C is the amount of asset() tokens in the pool

  • B is reserveWithSlippage

  • L is totalLiabilities The excess liquidity is a fixed point number using the decimals of this pool

Return Values

Name
Type
Description

excessLiquidity_

int256

The total excess liquidity of this pool, can be negative

sharesTargetWorth

function sharesTargetWorth(uint256 _sharesToBurn) public view returns (uint256 amount_)

Returns the worth of an amount of pool shares (LP tokens) in underlying principle

Parameters

Name
Type
Description

_sharesToBurn

uint256

The number of LP tokens to burn

Return Values

Name
Type
Description

amount_

uint256

The amount of asset() tokens that the shares are worth

swapFees

function swapFees() public view returns (uint256 lpFee_, uint256 backstopFee_, uint256 protocolFee_)

Return the configured swap fees for this pool

Return Values

Name
Type
Description

lpFee_

uint256

Fee that benefits the pool's LPers, in 0.0001% (e.g. 300 -> 0.0300%)

backstopFee_

uint256

Fee that benefits the backstop pool, in 0.0001% (e.g. 150 -> 0.0150%)

protocolFee_

uint256

Fee that benefits the protocol, in 0.0001% (e.g. 50 -> 0.0050%)

depositingUnfreezesAt

function depositingUnfreezesAt() public view returns (uint256 depositingUnfreezesAt_)
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