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TroveManager.sol
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TroveManager.sol
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// SPDX-License-Identifier: MIT
pragma solidity 0.8.0;
import "./Interfaces/ITroveManager.sol";
import "./Interfaces/IStabilityPool.sol";
import "./Interfaces/ICollSurplusPool.sol";
import "./Interfaces/IARTHValuecoin.sol";
import "./Interfaces/ISortedTroves.sol";
import "./Dependencies/LiquityBase.sol";
import "./Dependencies/Ownable.sol";
import "./Dependencies/CheckContract.sol";
contract TroveManager is LiquityBase, Ownable, CheckContract, ITroveManager {
string public constant NAME = "TroveManager";
using SafeMath for uint256;
// --- Connected contract declarations ---
address public borrowerOperationsAddress;
IStabilityPool public override stabilityPool;
address gasPoolAddress;
ICollSurplusPool collSurplusPool;
IARTHValuecoin public override arthToken;
// A doubly linked list of Troves, sorted by their sorted by their collateral ratios
ISortedTroves public sortedTroves;
// --- Data structures ---
uint256 public constant SECONDS_IN_ONE_MINUTE = 60;
/*
* Half-life of 12h. 12h = 720 min
* (1/2) = d^720 => d = (1/2)^(1/720)
*/
uint256 public constant MINUTE_DECAY_FACTOR = 999037758833783000;
// During bootsrap period redemptions are not allowed
uint256 public constant BOOTSTRAP_PERIOD = 7 days;
/*
* BETA: 18 digit decimal. Parameter by which to divide the redeemed fraction, in order to calc the new base rate from a redemption.
* Corresponds to (1 / ALPHA) in the white paper.
*/
uint256 public constant BETA = 2;
uint256 public baseRate;
// The timestamp of the latest fee operation (redemption or new ARTH issuance)
uint256 public lastFeeOperationTime;
enum Status {
nonExistent,
active,
closedByOwner,
closedByLiquidation,
closedByRedemption
}
// Store the necessary data for a trove
struct Trove {
uint256 debt;
uint256 coll;
uint256 stake;
Status status;
uint128 arrayIndex;
address frontEndTag;
}
mapping(address => Trove) public Troves;
uint256 public totalStakes;
// Snapshot of the value of totalStakes, taken immediately after the latest liquidation
uint256 public totalStakesSnapshot;
// Snapshot of the total collateral across the ActivePool and DefaultPool, immediately after the latest liquidation.
uint256 public totalCollateralSnapshot;
/*
* L_ETH and L_ARTHDebt track the sums of accumulated liquidation rewards per unit staked. During its lifetime, each stake earns:
*
* An ETH gain of ( stake * [L_ETH - L_ETH(0)] )
* A ARTHDebt increase of ( stake * [L_ARTHDebt - L_ARTHDebt(0)] )
*
* Where L_ETH(0) and L_ARTHDebt(0) are snapshots of L_ETH and L_ARTHDebt for the active Trove taken at the instant the stake was made
*/
uint256 public L_ETH;
uint256 public L_ARTHDebt;
// Map addresses with active troves to their RewardSnapshot
mapping(address => RewardSnapshot) public rewardSnapshots;
// Object containing the ETH and ARTH snapshots for a given active trove
struct RewardSnapshot {
uint256 ETH;
uint256 ARTHDebt;
}
// Array of all active trove addresses - used to to compute an approximate hint off-chain, for the sorted list insertion
address[] public TroveOwners;
// Error trackers for the trove redistribution calculation
uint256 public lastETHError_Redistribution;
uint256 public lastARTHDebtError_Redistribution;
/*
* --- Variable container structs for liquidations ---
*
* These structs are used to hold, return and assign variables inside the liquidation functions,
* in order to avoid the error: "CompilerError: Stack too deep".
**/
struct LocalVariables_OuterLiquidationFunction {
uint256 price;
uint256 ARTHInStabPool;
bool recoveryModeAtStart;
uint256 liquidatedDebt;
uint256 liquidatedColl;
}
struct LocalVariables_InnerSingleLiquidateFunction {
uint256 collToLiquidate;
uint256 pendingDebtReward;
uint256 pendingCollReward;
}
struct LocalVariables_LiquidationSequence {
uint256 remainingARTHInStabPool;
uint256 i;
uint256 ICR;
address user;
bool backToNormalMode;
uint256 entireSystemDebt;
uint256 entireSystemColl;
}
struct LiquidationValues {
uint256 entireTroveDebt;
uint256 entireTroveColl;
uint256 collGasCompensation;
uint256 ARTHGasCompensation;
uint256 debtToOffset;
uint256 collToSendToSP;
uint256 debtToRedistribute;
uint256 collToRedistribute;
uint256 collSurplus;
}
struct LiquidationTotals {
uint256 totalCollInSequence;
uint256 totalDebtInSequence;
uint256 totalCollGasCompensation;
uint256 totalARTHGasCompensation;
uint256 totalDebtToOffset;
uint256 totalCollToSendToSP;
uint256 totalDebtToRedistribute;
uint256 totalCollToRedistribute;
uint256 totalCollSurplus;
}
struct ContractsCache {
IActivePool activePool;
IDefaultPool defaultPool;
IARTHValuecoin arthToken;
IGovernance governance;
ISortedTroves sortedTroves;
ICollSurplusPool collSurplusPool;
address gasPoolAddress;
}
// --- Variable container structs for redemptions ---
struct RedemptionTotals {
uint256 remainingARTH;
uint256 totalARTHToRedeem;
uint256 totalETHDrawn;
uint256 ETHFee;
uint256 ETHToSendToRedeemer;
uint256 decayedBaseRate;
uint256 price;
uint256 totalARTHSupplyAtStart;
}
struct SingleRedemptionValues {
uint256 ARTHLot;
uint256 ETHLot;
bool cancelledPartial;
}
// --- Dependency setter ---
function setAddresses(
address _borrowerOperationsAddress,
address _activePoolAddress,
address _defaultPoolAddress,
address _stabilityPoolAddress,
address _gasPoolAddress,
address _collSurplusPoolAddress,
address _governanceAddress,
address _arthTokenAddress,
address _sortedTrovesAddress
) external override onlyOwner {
checkContract(_borrowerOperationsAddress);
checkContract(_activePoolAddress);
checkContract(_defaultPoolAddress);
checkContract(_stabilityPoolAddress);
checkContract(_gasPoolAddress);
checkContract(_collSurplusPoolAddress);
checkContract(_governanceAddress);
checkContract(_arthTokenAddress);
checkContract(_sortedTrovesAddress);
borrowerOperationsAddress = _borrowerOperationsAddress;
activePool = IActivePool(_activePoolAddress);
defaultPool = IDefaultPool(_defaultPoolAddress);
stabilityPool = IStabilityPool(_stabilityPoolAddress);
gasPoolAddress = _gasPoolAddress;
collSurplusPool = ICollSurplusPool(_collSurplusPoolAddress);
governance = IGovernance(_governanceAddress);
arthToken = IARTHValuecoin(_arthTokenAddress);
sortedTroves = ISortedTroves(_sortedTrovesAddress);
emit BorrowerOperationsAddressChanged(_borrowerOperationsAddress);
emit ActivePoolAddressChanged(_activePoolAddress);
emit DefaultPoolAddressChanged(_defaultPoolAddress);
emit StabilityPoolAddressChanged(_stabilityPoolAddress);
emit GasPoolAddressChanged(_gasPoolAddress);
emit CollSurplusPoolAddressChanged(_collSurplusPoolAddress);
emit GovernanceAddressChanged(_governanceAddress);
emit ARTHTokenAddressChanged(_arthTokenAddress);
emit SortedTrovesAddressChanged(_sortedTrovesAddress);
_renounceOwnership();
}
// --- Getters ---
function getTroveOwnersCount() external view override returns (uint256) {
return TroveOwners.length;
}
function getTroveFromTroveOwnersArray(uint256 _index) external view override returns (address) {
return TroveOwners[_index];
}
// --- Trove Liquidation functions ---
// Single liquidation function. Closes the trove if its ICR is lower than the minimum collateral ratio.
function liquidate(address _borrower) external override {
_requireTroveIsActive(_borrower);
address[] memory borrowers = new address[](1);
borrowers[0] = _borrower;
batchLiquidateTroves(borrowers);
}
// --- Inner single liquidation functions ---
// Liquidate one trove, in Normal Mode.
function _liquidateNormalMode(
IActivePool _activePool,
IDefaultPool _defaultPool,
address _borrower,
uint256 _ARTHInStabPool
) internal returns (LiquidationValues memory singleLiquidation) {
LocalVariables_InnerSingleLiquidateFunction memory vars;
(
singleLiquidation.entireTroveDebt,
singleLiquidation.entireTroveColl,
vars.pendingDebtReward,
vars.pendingCollReward
) = getEntireDebtAndColl(_borrower);
_movePendingTroveRewardsToActivePool(
_activePool,
_defaultPool,
vars.pendingDebtReward,
vars.pendingCollReward
);
_removeStake(_borrower);
singleLiquidation.collGasCompensation = _getCollGasCompensation(
singleLiquidation.entireTroveColl
);
singleLiquidation.ARTHGasCompensation = ARTH_GAS_COMPENSATION();
uint256 collToLiquidate = singleLiquidation.entireTroveColl.sub(
singleLiquidation.collGasCompensation
);
(
singleLiquidation.debtToOffset,
singleLiquidation.collToSendToSP,
singleLiquidation.debtToRedistribute,
singleLiquidation.collToRedistribute
) = _getOffsetAndRedistributionVals(
singleLiquidation.entireTroveDebt,
collToLiquidate,
_ARTHInStabPool
);
_closeTrove(_borrower, Status.closedByLiquidation);
emit TroveLiquidated(
_borrower,
singleLiquidation.entireTroveDebt,
singleLiquidation.entireTroveColl,
TroveManagerOperation.liquidateInNormalMode
);
emit TroveUpdated(_borrower, 0, 0, 0, TroveManagerOperation.liquidateInNormalMode);
return singleLiquidation;
}
// Liquidate one trove, in Recovery Mode.
function _liquidateRecoveryMode(
IActivePool _activePool,
IDefaultPool _defaultPool,
address _borrower,
uint256 _ICR,
uint256 _ARTHInStabPool,
uint256 _TCR,
uint256 _price
) internal returns (LiquidationValues memory singleLiquidation) {
LocalVariables_InnerSingleLiquidateFunction memory vars;
if (TroveOwners.length <= 1) {
return singleLiquidation;
} // don't liquidate if last trove
(
singleLiquidation.entireTroveDebt,
singleLiquidation.entireTroveColl,
vars.pendingDebtReward,
vars.pendingCollReward
) = getEntireDebtAndColl(_borrower);
singleLiquidation.collGasCompensation = _getCollGasCompensation(
singleLiquidation.entireTroveColl
);
singleLiquidation.ARTHGasCompensation = ARTH_GAS_COMPENSATION();
vars.collToLiquidate = singleLiquidation.entireTroveColl.sub(
singleLiquidation.collGasCompensation
);
// If ICR <= 100%, purely redistribute the Trove across all active Troves
if (_ICR <= _100pct) {
_movePendingTroveRewardsToActivePool(
_activePool,
_defaultPool,
vars.pendingDebtReward,
vars.pendingCollReward
);
_removeStake(_borrower);
singleLiquidation.debtToOffset = 0;
singleLiquidation.collToSendToSP = 0;
singleLiquidation.debtToRedistribute = singleLiquidation.entireTroveDebt;
singleLiquidation.collToRedistribute = vars.collToLiquidate;
_closeTrove(_borrower, Status.closedByLiquidation);
emit TroveLiquidated(
_borrower,
singleLiquidation.entireTroveDebt,
singleLiquidation.entireTroveColl,
TroveManagerOperation.liquidateInRecoveryMode
);
emit TroveUpdated(_borrower, 0, 0, 0, TroveManagerOperation.liquidateInRecoveryMode);
// If 100% < ICR < MCR, offset as much as possible, and redistribute the remainder
} else if ((_ICR > _100pct) && (_ICR < MCR)) {
_movePendingTroveRewardsToActivePool(
_activePool,
_defaultPool,
vars.pendingDebtReward,
vars.pendingCollReward
);
_removeStake(_borrower);
(
singleLiquidation.debtToOffset,
singleLiquidation.collToSendToSP,
singleLiquidation.debtToRedistribute,
singleLiquidation.collToRedistribute
) = _getOffsetAndRedistributionVals(
singleLiquidation.entireTroveDebt,
vars.collToLiquidate,
_ARTHInStabPool
);
_closeTrove(_borrower, Status.closedByLiquidation);
emit TroveLiquidated(
_borrower,
singleLiquidation.entireTroveDebt,
singleLiquidation.entireTroveColl,
TroveManagerOperation.liquidateInRecoveryMode
);
emit TroveUpdated(_borrower, 0, 0, 0, TroveManagerOperation.liquidateInRecoveryMode);
/*
* If 110% <= ICR < current TCR (accounting for the preceding liquidations in the current sequence)
* and there is ARTH in the Stability Pool, only offset, with no redistribution,
* but at a capped rate of 1.1 and only if the whole debt can be liquidated.
* The remainder due to the capped rate will be claimable as collateral surplus.
*/
} else if (
(_ICR >= MCR) && (_ICR < _TCR) && (singleLiquidation.entireTroveDebt <= _ARTHInStabPool)
) {
_movePendingTroveRewardsToActivePool(
_activePool,
_defaultPool,
vars.pendingDebtReward,
vars.pendingCollReward
);
assert(_ARTHInStabPool != 0);
_removeStake(_borrower);
singleLiquidation = _getCappedOffsetVals(
singleLiquidation.entireTroveDebt,
singleLiquidation.entireTroveColl,
_price
);
_closeTrove(_borrower, Status.closedByLiquidation);
if (singleLiquidation.collSurplus > 0) {
collSurplusPool.accountSurplus(_borrower, singleLiquidation.collSurplus);
}
emit TroveLiquidated(
_borrower,
singleLiquidation.entireTroveDebt,
singleLiquidation.collToSendToSP,
TroveManagerOperation.liquidateInRecoveryMode
);
emit TroveUpdated(_borrower, 0, 0, 0, TroveManagerOperation.liquidateInRecoveryMode);
} else {
// if (_ICR >= MCR && ( _ICR >= _TCR || singleLiquidation.entireTroveDebt > _ARTHInStabPool))
LiquidationValues memory zeroVals;
return zeroVals;
}
return singleLiquidation;
}
/* In a full liquidation, returns the values for a trove's coll and debt to be offset, and coll and debt to be
* redistributed to active troves.
*/
function _getOffsetAndRedistributionVals(
uint256 _debt,
uint256 _coll,
uint256 _ARTHInStabPool
)
internal
pure
returns (
uint256 debtToOffset,
uint256 collToSendToSP,
uint256 debtToRedistribute,
uint256 collToRedistribute
)
{
if (_ARTHInStabPool > 0) {
/*
* Offset as much debt & collateral as possible against the Stability Pool, and redistribute the remainder
* between all active troves.
*
* If the trove's debt is larger than the deposited ARTH in the Stability Pool:
*
* - Offset an amount of the trove's debt equal to the ARTH in the Stability Pool
* - Send a fraction of the trove's collateral to the Stability Pool, equal to the fraction of its offset debt
*
*/
debtToOffset = LiquityMath._min(_debt, _ARTHInStabPool);
collToSendToSP = _coll.mul(debtToOffset).div(_debt);
debtToRedistribute = _debt.sub(debtToOffset);
collToRedistribute = _coll.sub(collToSendToSP);
} else {
debtToOffset = 0;
collToSendToSP = 0;
debtToRedistribute = _debt;
collToRedistribute = _coll;
}
}
/*
* Get its offset coll/debt and ETH gas comp, and close the trove.
*/
function _getCappedOffsetVals(
uint256 _entireTroveDebt,
uint256 _entireTroveColl,
uint256 _price
) internal view returns (LiquidationValues memory singleLiquidation) {
singleLiquidation.entireTroveDebt = _entireTroveDebt;
singleLiquidation.entireTroveColl = _entireTroveColl;
uint256 cappedCollPortion = _entireTroveDebt.mul(MCR).div(_price);
singleLiquidation.collGasCompensation = _getCollGasCompensation(cappedCollPortion);
singleLiquidation.ARTHGasCompensation = ARTH_GAS_COMPENSATION();
singleLiquidation.debtToOffset = _entireTroveDebt;
singleLiquidation.collToSendToSP = cappedCollPortion.sub(
singleLiquidation.collGasCompensation
);
singleLiquidation.collSurplus = _entireTroveColl.sub(cappedCollPortion);
singleLiquidation.debtToRedistribute = 0;
singleLiquidation.collToRedistribute = 0;
}
/*
* Liquidate a sequence of troves. Closes a maximum number of n under-collateralized Troves,
* starting from the one with the lowest collateral ratio in the system, and moving upwards
*/
function liquidateTroves(uint256 _n) external override {
ContractsCache memory contractsCache = ContractsCache(
activePool,
defaultPool,
IARTHValuecoin(address(0)),
IGovernance(address(0)),
sortedTroves,
ICollSurplusPool(address(0)),
address(0)
);
IStabilityPool stabilityPoolCached = stabilityPool;
LocalVariables_OuterLiquidationFunction memory vars;
LiquidationTotals memory totals;
vars.price = getPriceFeed().fetchPrice();
vars.ARTHInStabPool = stabilityPoolCached.getTotalARTHDeposits();
vars.recoveryModeAtStart = _checkRecoveryMode(vars.price);
// Perform the appropriate liquidation sequence - tally the values, and obtain their totals
if (vars.recoveryModeAtStart) {
totals = _getTotalsFromLiquidateTrovesSequence_RecoveryMode(
contractsCache,
vars.price,
vars.ARTHInStabPool,
_n
);
} else {
// if !vars.recoveryModeAtStart
totals = _getTotalsFromLiquidateTrovesSequence_NormalMode(
contractsCache.activePool,
contractsCache.defaultPool,
vars.price,
vars.ARTHInStabPool,
_n
);
}
require(totals.totalDebtInSequence > 0, "TroveManager: nothing to liquidate");
// Move liquidated ETH and ARTH to the appropriate pools
stabilityPoolCached.offset(totals.totalDebtToOffset, totals.totalCollToSendToSP);
_redistributeDebtAndColl(
contractsCache.activePool,
contractsCache.defaultPool,
totals.totalDebtToRedistribute,
totals.totalCollToRedistribute
);
if (totals.totalCollSurplus > 0) {
contractsCache.activePool.sendETH(address(collSurplusPool), totals.totalCollSurplus);
}
// Update system snapshots
_updateSystemSnapshots_excludeCollRemainder(
contractsCache.activePool,
totals.totalCollGasCompensation
);
vars.liquidatedDebt = totals.totalDebtInSequence;
vars.liquidatedColl = totals.totalCollInSequence.sub(totals.totalCollGasCompensation).sub(
totals.totalCollSurplus
);
emit Liquidation(
vars.liquidatedDebt,
vars.liquidatedColl,
totals.totalCollGasCompensation,
totals.totalARTHGasCompensation
);
// Send gas compensation to caller
_sendGasCompensation(
contractsCache.activePool,
msg.sender,
totals.totalARTHGasCompensation,
totals.totalCollGasCompensation
);
}
/*
* This function is used when the liquidateTroves sequence starts during Recovery Mode. However, it
* handle the case where the system *leaves* Recovery Mode, part way through the liquidation sequence
*/
function _getTotalsFromLiquidateTrovesSequence_RecoveryMode(
ContractsCache memory _contractsCache,
uint256 _price,
uint256 _ARTHInStabPool,
uint256 _n
) internal returns (LiquidationTotals memory totals) {
LocalVariables_LiquidationSequence memory vars;
LiquidationValues memory singleLiquidation;
vars.remainingARTHInStabPool = _ARTHInStabPool;
vars.backToNormalMode = false;
vars.entireSystemDebt = getEntireSystemDebt();
vars.entireSystemColl = getEntireSystemColl();
vars.user = _contractsCache.sortedTroves.getLast();
address firstUser = _contractsCache.sortedTroves.getFirst();
for (vars.i = 0; vars.i < _n && vars.user != firstUser; vars.i++) {
// we need to cache it, because current user is likely going to be deleted
address nextUser = _contractsCache.sortedTroves.getPrev(vars.user);
vars.ICR = getCurrentICR(vars.user, _price);
if (!vars.backToNormalMode) {
// Break the loop if ICR is greater than MCR and Stability Pool is empty
if (vars.ICR >= MCR && vars.remainingARTHInStabPool == 0) {
break;
}
uint256 TCR = LiquityMath._computeCR(
vars.entireSystemColl,
vars.entireSystemDebt,
_price
);
singleLiquidation = _liquidateRecoveryMode(
_contractsCache.activePool,
_contractsCache.defaultPool,
vars.user,
vars.ICR,
vars.remainingARTHInStabPool,
TCR,
_price
);
// Update aggregate trackers
vars.remainingARTHInStabPool = vars.remainingARTHInStabPool.sub(
singleLiquidation.debtToOffset
);
vars.entireSystemDebt = vars.entireSystemDebt.sub(singleLiquidation.debtToOffset);
vars.entireSystemColl = vars
.entireSystemColl
.sub(singleLiquidation.collToSendToSP)
.sub(singleLiquidation.collGasCompensation)
.sub(singleLiquidation.collSurplus);
// Add liquidation values to their respective running totals
totals = _addLiquidationValuesToTotals(totals, singleLiquidation);
vars.backToNormalMode = !_checkPotentialRecoveryMode(
vars.entireSystemColl,
vars.entireSystemDebt,
_price
);
} else if (vars.backToNormalMode && vars.ICR < MCR) {
singleLiquidation = _liquidateNormalMode(
_contractsCache.activePool,
_contractsCache.defaultPool,
vars.user,
vars.remainingARTHInStabPool
);
vars.remainingARTHInStabPool = vars.remainingARTHInStabPool.sub(
singleLiquidation.debtToOffset
);
// Add liquidation values to their respective running totals
totals = _addLiquidationValuesToTotals(totals, singleLiquidation);
} else break; // break if the loop reaches a Trove with ICR >= MCR
vars.user = nextUser;
}
}
function _getTotalsFromLiquidateTrovesSequence_NormalMode(
IActivePool _activePool,
IDefaultPool _defaultPool,
uint256 _price,
uint256 _ARTHInStabPool,
uint256 _n
) internal returns (LiquidationTotals memory totals) {
LocalVariables_LiquidationSequence memory vars;
LiquidationValues memory singleLiquidation;
ISortedTroves sortedTrovesCached = sortedTroves;
vars.remainingARTHInStabPool = _ARTHInStabPool;
for (vars.i = 0; vars.i < _n; vars.i++) {
vars.user = sortedTrovesCached.getLast();
vars.ICR = getCurrentICR(vars.user, _price);
if (vars.ICR < MCR) {
singleLiquidation = _liquidateNormalMode(
_activePool,
_defaultPool,
vars.user,
vars.remainingARTHInStabPool
);
vars.remainingARTHInStabPool = vars.remainingARTHInStabPool.sub(
singleLiquidation.debtToOffset
);
// Add liquidation values to their respective running totals
totals = _addLiquidationValuesToTotals(totals, singleLiquidation);
} else break; // break if the loop reaches a Trove with ICR >= MCR
}
}
/*
* Attempt to liquidate a custom list of troves provided by the caller.
*/
function batchLiquidateTroves(address[] memory _troveArray) public override {
require(_troveArray.length != 0, "TroveManager: Calldata address array must not be empty");
IActivePool activePoolCached = activePool;
IDefaultPool defaultPoolCached = defaultPool;
IStabilityPool stabilityPoolCached = stabilityPool;
LocalVariables_OuterLiquidationFunction memory vars;
LiquidationTotals memory totals;
vars.price = getPriceFeed().fetchPrice();
vars.ARTHInStabPool = stabilityPoolCached.getTotalARTHDeposits();
vars.recoveryModeAtStart = _checkRecoveryMode(vars.price);
// Perform the appropriate liquidation sequence - tally values and obtain their totals.
if (vars.recoveryModeAtStart) {
totals = _getTotalFromBatchLiquidate_RecoveryMode(
activePoolCached,
defaultPoolCached,
vars.price,
vars.ARTHInStabPool,
_troveArray
);
} else {
// if !vars.recoveryModeAtStart
totals = _getTotalsFromBatchLiquidate_NormalMode(
activePoolCached,
defaultPoolCached,
vars.price,
vars.ARTHInStabPool,
_troveArray
);
}
require(totals.totalDebtInSequence > 0, "TroveManager: nothing to liquidate");
// Move liquidated ETH and ARTH to the appropriate pools
stabilityPoolCached.offset(totals.totalDebtToOffset, totals.totalCollToSendToSP);
_redistributeDebtAndColl(
activePoolCached,
defaultPoolCached,
totals.totalDebtToRedistribute,
totals.totalCollToRedistribute
);
if (totals.totalCollSurplus > 0) {
activePoolCached.sendETH(address(collSurplusPool), totals.totalCollSurplus);
}
// Update system snapshots
_updateSystemSnapshots_excludeCollRemainder(
activePoolCached,
totals.totalCollGasCompensation
);
vars.liquidatedDebt = totals.totalDebtInSequence;
vars.liquidatedColl = totals.totalCollInSequence.sub(totals.totalCollGasCompensation).sub(
totals.totalCollSurplus
);
emit Liquidation(
vars.liquidatedDebt,
vars.liquidatedColl,
totals.totalCollGasCompensation,
totals.totalARTHGasCompensation
);
// Send gas compensation to caller
_sendGasCompensation(
activePoolCached,
msg.sender,
totals.totalARTHGasCompensation,
totals.totalCollGasCompensation
);
}
/*
* This function is used when the batch liquidation sequence starts during Recovery Mode. However, it
* handle the case where the system *leaves* Recovery Mode, part way through the liquidation sequence
*/
function _getTotalFromBatchLiquidate_RecoveryMode(
IActivePool _activePool,
IDefaultPool _defaultPool,
uint256 _price,
uint256 _ARTHInStabPool,
address[] memory _troveArray
) internal returns (LiquidationTotals memory totals) {
LocalVariables_LiquidationSequence memory vars;
LiquidationValues memory singleLiquidation;
vars.remainingARTHInStabPool = _ARTHInStabPool;
vars.backToNormalMode = false;
vars.entireSystemDebt = getEntireSystemDebt();
vars.entireSystemColl = getEntireSystemColl();
for (vars.i = 0; vars.i < _troveArray.length; vars.i++) {
vars.user = _troveArray[vars.i];
// Skip non-active troves
if (Troves[vars.user].status != Status.active) {
continue;
}
vars.ICR = getCurrentICR(vars.user, _price);
if (!vars.backToNormalMode) {
// Skip this trove if ICR is greater than MCR and Stability Pool is empty
if (vars.ICR >= MCR && vars.remainingARTHInStabPool == 0) {
continue;
}
uint256 TCR = LiquityMath._computeCR(
vars.entireSystemColl,
vars.entireSystemDebt,
_price
);
singleLiquidation = _liquidateRecoveryMode(
_activePool,
_defaultPool,
vars.user,
vars.ICR,
vars.remainingARTHInStabPool,
TCR,
_price
);
// Update aggregate trackers
vars.remainingARTHInStabPool = vars.remainingARTHInStabPool.sub(
singleLiquidation.debtToOffset
);
vars.entireSystemDebt = vars.entireSystemDebt.sub(singleLiquidation.debtToOffset);
vars.entireSystemColl = vars
.entireSystemColl
.sub(singleLiquidation.collToSendToSP)
.sub(singleLiquidation.collGasCompensation)
.sub(singleLiquidation.collSurplus);
// Add liquidation values to their respective running totals
totals = _addLiquidationValuesToTotals(totals, singleLiquidation);
vars.backToNormalMode = !_checkPotentialRecoveryMode(
vars.entireSystemColl,
vars.entireSystemDebt,
_price
);
} else if (vars.backToNormalMode && vars.ICR < MCR) {
singleLiquidation = _liquidateNormalMode(
_activePool,
_defaultPool,
vars.user,
vars.remainingARTHInStabPool
);
vars.remainingARTHInStabPool = vars.remainingARTHInStabPool.sub(
singleLiquidation.debtToOffset
);
// Add liquidation values to their respective running totals
totals = _addLiquidationValuesToTotals(totals, singleLiquidation);
} else continue; // In Normal Mode skip troves with ICR >= MCR
}
}
function _getTotalsFromBatchLiquidate_NormalMode(
IActivePool _activePool,
IDefaultPool _defaultPool,
uint256 _price,
uint256 _ARTHInStabPool,
address[] memory _troveArray
) internal returns (LiquidationTotals memory totals) {
LocalVariables_LiquidationSequence memory vars;
LiquidationValues memory singleLiquidation;
vars.remainingARTHInStabPool = _ARTHInStabPool;
for (vars.i = 0; vars.i < _troveArray.length; vars.i++) {
vars.user = _troveArray[vars.i];
vars.ICR = getCurrentICR(vars.user, _price);
if (vars.ICR < MCR) {
singleLiquidation = _liquidateNormalMode(
_activePool,
_defaultPool,
vars.user,
vars.remainingARTHInStabPool
);
vars.remainingARTHInStabPool = vars.remainingARTHInStabPool.sub(
singleLiquidation.debtToOffset
);
// Add liquidation values to their respective running totals
totals = _addLiquidationValuesToTotals(totals, singleLiquidation);
}
}
}
// --- Liquidation helper functions ---
function _addLiquidationValuesToTotals(
LiquidationTotals memory oldTotals,
LiquidationValues memory singleLiquidation
) internal pure returns (LiquidationTotals memory newTotals) {
// Tally all the values with their respective running totals
newTotals.totalCollGasCompensation = oldTotals.totalCollGasCompensation.add(
singleLiquidation.collGasCompensation
);
newTotals.totalARTHGasCompensation = oldTotals.totalARTHGasCompensation.add(
singleLiquidation.ARTHGasCompensation
);
newTotals.totalDebtInSequence = oldTotals.totalDebtInSequence.add(
singleLiquidation.entireTroveDebt
);
newTotals.totalCollInSequence = oldTotals.totalCollInSequence.add(
singleLiquidation.entireTroveColl
);
newTotals.totalDebtToOffset = oldTotals.totalDebtToOffset.add(
singleLiquidation.debtToOffset
);
newTotals.totalCollToSendToSP = oldTotals.totalCollToSendToSP.add(
singleLiquidation.collToSendToSP
);
newTotals.totalDebtToRedistribute = oldTotals.totalDebtToRedistribute.add(
singleLiquidation.debtToRedistribute
);
newTotals.totalCollToRedistribute = oldTotals.totalCollToRedistribute.add(
singleLiquidation.collToRedistribute
);
newTotals.totalCollSurplus = oldTotals.totalCollSurplus.add(singleLiquidation.collSurplus);
return newTotals;
}
function _sendGasCompensation(
IActivePool _activePool,
address _liquidator,
uint256 _ARTH,
uint256 _ETH
) internal {
if (_ARTH > 0) {
arthToken.returnFromPool(gasPoolAddress, _liquidator, _ARTH);
}
if (_ETH > 0) {
_activePool.sendETH(_liquidator, _ETH);
}
}
// Move a Trove's pending debt and collateral rewards from distributions, from the Default Pool to the Active Pool
function _movePendingTroveRewardsToActivePool(
IActivePool _activePool,
IDefaultPool _defaultPool,
uint256 _ARTH,
uint256 _ETH
) internal {
_defaultPool.decreaseARTHDebt(_ARTH);
_activePool.increaseARTHDebt(_ARTH);
_defaultPool.sendETHToActivePool(_ETH);
}
// --- Redemption functions ---
// Redeem as much collateral as possible from _borrower's Trove in exchange for ARTH up to _maxARTHamount
function _redeemCollateralFromTrove(
ContractsCache memory _contractsCache,
address _borrower,
uint256 _maxARTHamount,
uint256 _price,
address _upperPartialRedemptionHint,
address _lowerPartialRedemptionHint,
uint256 _partialRedemptionHintNICR
) internal returns (SingleRedemptionValues memory singleRedemption) {
// Determine the remaining amount (lot) to be redeemed, capped by the entire debt of the Trove minus the liquidation reserve
singleRedemption.ARTHLot = LiquityMath._min(
_maxARTHamount,
Troves[_borrower].debt.sub(ARTH_GAS_COMPENSATION())
);
// Get the ETHLot of equivalent value in USD
singleRedemption.ETHLot = singleRedemption.ARTHLot.mul(DECIMAL_PRECISION).div(_price);
// Decrease the debt and collateral of the current Trove according to the ARTH lot and corresponding ETH to send
uint256 newDebt = (Troves[_borrower].debt).sub(singleRedemption.ARTHLot);
uint256 newColl = (Troves[_borrower].coll).sub(singleRedemption.ETHLot);
if (newDebt == ARTH_GAS_COMPENSATION()) {
// No debt left in the Trove (except for the liquidation reserve), therefore the trove gets closed
_removeStake(_borrower);
_closeTrove(_borrower, Status.closedByRedemption);
_redeemCloseTrove(_contractsCache, _borrower, ARTH_GAS_COMPENSATION(), newColl);