Alpheratz release 2.69.0 (Synthetixio#1783)

Author: barrasso

contracts/BaseSynthetix.sol

@@ -13,6 +13,8 @@ import "./interfaces/ISystemStatus.sol";
 import "./interfaces/IExchanger.sol";
 import "./interfaces/IIssuer.sol";
 import "./interfaces/IRewardsDistribution.sol";
+import "./interfaces/ILiquidator.sol";
+import "./interfaces/ILiquidatorRewards.sol";
 import "./interfaces/IVirtualSynth.sol";
 
 contract BaseSynthetix is IERC20, ExternStateToken, MixinResolver, ISynthetix {
@@ -29,6 +31,8 @@ contract BaseSynthetix is IERC20, ExternStateToken, MixinResolver, ISynthetix {
     bytes32 private constant CONTRACT_EXCHANGER = "Exchanger";
     bytes32 private constant CONTRACT_ISSUER = "Issuer";
     bytes32 private constant CONTRACT_REWARDSDISTRIBUTION = "RewardsDistribution";
+    bytes32 private constant CONTRACT_LIQUIDATORREWARDS = "LiquidatorRewards";
+    bytes32 private constant CONTRACT_LIQUIDATOR = "Liquidator";
 
     // ========== CONSTRUCTOR ==========
 
@@ -48,11 +52,13 @@ contract BaseSynthetix is IERC20, ExternStateToken, MixinResolver, ISynthetix {
 
     // Note: use public visibility so that it can be invoked in a subclass
     function resolverAddressesRequired() public view returns (bytes32[] memory addresses) {
-        addresses = new bytes32[](4);
+        addresses = new bytes32[](6);
         addresses[0] = CONTRACT_SYSTEMSTATUS;
         addresses[1] = CONTRACT_EXCHANGER;
         addresses[2] = CONTRACT_ISSUER;
         addresses[3] = CONTRACT_REWARDSDISTRIBUTION;
+        addresses[4] = CONTRACT_LIQUIDATORREWARDS;
+        addresses[5] = CONTRACT_LIQUIDATOR;
     }
 
     function systemStatus() internal view returns (ISystemStatus) {
@@ -71,6 +77,14 @@ contract BaseSynthetix is IERC20, ExternStateToken, MixinResolver, ISynthetix {
         return IRewardsDistribution(requireAndGetAddress(CONTRACT_REWARDSDISTRIBUTION));
     }
 
+    function liquidatorRewards() internal view returns (ILiquidatorRewards) {
+        return ILiquidatorRewards(requireAndGetAddress(CONTRACT_LIQUIDATORREWARDS));
+    }
+
+    function liquidator() internal view returns (ILiquidator) {
+        return ILiquidator(requireAndGetAddress(CONTRACT_LIQUIDATOR));
+    }
+
     function debtBalanceOf(address account, bytes32 currencyKey) external view returns (uint) {
         return issuer().debtBalanceOf(account, currencyKey);
     }
@@ -297,20 +311,66 @@ contract BaseSynthetix is IERC20, ExternStateToken, MixinResolver, ISynthetix {
         return issuer().burnSynthsToTargetOnBehalf(burnForAddress, messageSender);
     }
 
-    function liquidateDelinquentAccount(address account, uint susdAmount)
-        external
-        systemActive
-        optionalProxy
-        returns (bool)
-    {
-        (uint totalRedeemed, uint amountLiquidated) =
-            issuer().liquidateDelinquentAccount(account, susdAmount, messageSender);
+    /// @notice Force liquidate a delinquent account and distribute the redeemed SNX rewards amongst the appropriate recipients.
+    /// @dev The SNX transfers will revert if the amount to send is more than balanceOf account (i.e. due to escrowed balance).
+    function liquidateDelinquentAccount(address account) external systemActive optionalProxy returns (bool) {
+        (uint totalRedeemed, uint amountLiquidated) = issuer().liquidateAccount(account, false);
 
         emitAccountLiquidated(account, totalRedeemed, amountLiquidated, messageSender);
 
-        // Transfer SNX redeemed to messageSender
-        // Reverts if amount to redeem is more than balanceOf account, ie due to escrowed balance
-        return _transferByProxy(account, messageSender, totalRedeemed);
+        if (totalRedeemed > 0) {
+            uint stakerRewards; // The amount of rewards to be sent to the LiquidatorRewards contract.
+            uint flagReward = liquidator().flagReward();
+            uint liquidateReward = liquidator().liquidateReward();
+            // Check if the total amount of redeemed SNX is enough to payout the liquidation rewards.
+            if (totalRedeemed > flagReward.add(liquidateReward)) {
+                // Transfer the flagReward to the account who flagged this account for liquidation.
+                address flagger = liquidator().getLiquidationCallerForAccount(account);
+                bool flagRewardTransferSucceeded = _transferByProxy(account, flagger, flagReward);
+                require(flagRewardTransferSucceeded, "Flag reward transfer did not succeed");
+
+                // Transfer the liquidateReward to liquidator (the account who invoked this liquidation).
+                bool liquidateRewardTransferSucceeded = _transferByProxy(account, messageSender, liquidateReward);
+                require(liquidateRewardTransferSucceeded, "Liquidate reward transfer did not succeed");
+
+                // The remaining SNX to be sent to the LiquidatorRewards contract.
+                stakerRewards = totalRedeemed.sub(flagReward.add(liquidateReward));
+            } else {
+                /* If the total amount of redeemed SNX is greater than zero 
+                but is less than the sum of the flag & liquidate rewards,
+                then just send all of the SNX to the LiquidatorRewards contract. */
+                stakerRewards = totalRedeemed;
+            }
+
+            bool liquidatorRewardTransferSucceeded = _transferByProxy(account, address(liquidatorRewards()), stakerRewards);
+            require(liquidatorRewardTransferSucceeded, "Transfer to LiquidatorRewards failed");
+
+            // Inform the LiquidatorRewards contract about the incoming SNX rewards.
+            liquidatorRewards().notifyRewardAmount(stakerRewards);
+
+            return true;
+        } else {
+            // In this unlikely case, the total redeemed SNX is not greater than zero so don't perform any transfers.
+            return false;
+        }
+    }
+
+    /// @notice Allows an account to self-liquidate anytime its c-ratio is below the target issuance ratio.
+    function liquidateSelf() external systemActive optionalProxy returns (bool) {
+        // Self liquidate the account (`isSelfLiquidation` flag must be set to `true`).
+        (uint totalRedeemed, uint amountLiquidated) = issuer().liquidateAccount(messageSender, true);
+
+        emitAccountLiquidated(messageSender, totalRedeemed, amountLiquidated, messageSender);
+
+        // Transfer the redeemed SNX to the LiquidatorRewards contract.
+        // Reverts if amount to redeem is more than balanceOf account (i.e. due to escrowed balance).
+        bool success = _transferByProxy(messageSender, address(liquidatorRewards()), totalRedeemed);
+        require(success, "Transfer to LiquidatorRewards failed");
+
+        // Inform the LiquidatorRewards contract about the incoming SNX rewards.
+        liquidatorRewards().notifyRewardAmount(totalRedeemed);
+
+        return success;
     }
 
     function exchangeWithTrackingForInitiator(
@@ -369,7 +429,7 @@ contract BaseSynthetix is IERC20, ExternStateToken, MixinResolver, ISynthetix {
         _;
     }
 
-    function _systemActive() private {
+    function _systemActive() private view {
         systemStatus().requireSystemActive();
     }
 
@@ -378,7 +438,7 @@ contract BaseSynthetix is IERC20, ExternStateToken, MixinResolver, ISynthetix {
         _;
     }
 
-    function _issuanceActive() private {
+    function _issuanceActive() private view {
         systemStatus().requireIssuanceActive();
     }
 
@@ -387,7 +447,7 @@ contract BaseSynthetix is IERC20, ExternStateToken, MixinResolver, ISynthetix {
         _;
     }
 
-    function _exchangeActive(bytes32 src, bytes32 dest) private {
+    function _exchangeActive(bytes32 src, bytes32 dest) private view {
         systemStatus().requireExchangeBetweenSynthsAllowed(src, dest);
     }
 
@@ -396,7 +456,7 @@ contract BaseSynthetix is IERC20, ExternStateToken, MixinResolver, ISynthetix {
         _;
     }
 
-    function _onlyExchanger() private {
+    function _onlyExchanger() private view {
         require(msg.sender == address(exchanger()), "Only Exchanger can invoke this");
     }
 

contracts/Exchanger.sol

@@ -433,42 +433,38 @@ contract Exchanger is Owned, MixinSystemSettings, IExchanger {
             IVirtualSynth vSynth
         )
     {
+        require(sourceAmount > 0, "Zero amount");
+
         // Using struct to resolve stack too deep error
         IExchanger.ExchangeEntry memory entry;
 
         entry.roundIdForSrc = exchangeRates().getCurrentRoundId(sourceCurrencyKey);
         entry.roundIdForDest = exchangeRates().getCurrentRoundId(destinationCurrencyKey);
 
+        uint sourceAmountAfterSettlement = _settleAndCalcSourceAmountRemaining(sourceAmount, from, sourceCurrencyKey);
+
+        // If, after settlement the user has no balance left (highly unlikely), then return to prevent
+        // emitting events of 0 and don't revert so as to ensure the settlement queue is emptied
+        if (sourceAmountAfterSettlement == 0) {
+            return (0, 0, IVirtualSynth(0));
+        }
+
         (entry.destinationAmount, entry.sourceRate, entry.destinationRate) = exchangeRates().effectiveValueAndRatesAtRound(
             sourceCurrencyKey,
-            sourceAmount,
+            sourceAmountAfterSettlement,
             destinationCurrencyKey,
             entry.roundIdForSrc,
             entry.roundIdForDest
         );
 
-        _ensureCanExchangeAtRound(
-            sourceCurrencyKey,
-            sourceAmount,
-            destinationCurrencyKey,
-            entry.roundIdForSrc,
-            entry.roundIdForDest
-        );
+        _ensureCanExchangeAtRound(sourceCurrencyKey, destinationCurrencyKey, entry.roundIdForSrc, entry.roundIdForDest);
 
         // SIP-65: Decentralized Circuit Breaker
         // mutative call to suspend system if the rate is invalid
         if (_exchangeRatesCircuitBroken(sourceCurrencyKey, destinationCurrencyKey)) {
             return (0, 0, IVirtualSynth(0));
         }
 
-        uint sourceAmountAfterSettlement = _settleAndCalcSourceAmountRemaining(sourceAmount, from, sourceCurrencyKey);
-
-        // If, after settlement the user has no balance left (highly unlikely), then return to prevent
-        // emitting events of 0 and don't revert so as to ensure the settlement queue is emptied
-        if (sourceAmountAfterSettlement == 0) {
-            return (0, 0, IVirtualSynth(0));
-        }
-
         bool tooVolatile;
         (entry.exchangeFeeRate, tooVolatile) = _feeRateForExchangeAtRounds(
             sourceCurrencyKey,
@@ -642,13 +638,11 @@ contract Exchanger is Owned, MixinSystemSettings, IExchanger {
 
     function _ensureCanExchangeAtRound(
         bytes32 sourceCurrencyKey,
-        uint sourceAmount,
         bytes32 destinationCurrencyKey,
         uint roundIdForSrc,
         uint roundIdForDest
     ) internal view {
         require(sourceCurrencyKey != destinationCurrencyKey, "Can't be same synth");
-        require(sourceAmount > 0, "Zero amount");
 
         bytes32[] memory synthKeys = new bytes32[](2);
         synthKeys[0] = sourceCurrencyKey;

contracts/ExchangerWithFeeRecAlternatives.sol

@@ -186,7 +186,7 @@ contract ExchangerWithFeeRecAlternatives is MinimalProxyFactory, Exchanger {
         } else {
             // Otherwise, convert source to sUSD value
             (uint amountReceivedInUSD, uint sUsdFee, , , , ) =
-                _getAmountsForAtomicExchangeMinusFees(sourceAmount, sourceCurrencyKey, sUSD);
+                _getAmountsForAtomicExchangeMinusFees(sourceAmountAfterSettlement, sourceCurrencyKey, sUSD);
             sourceSusdValue = amountReceivedInUSD.add(sUsdFee);
         }