Merge pull request #725 from bgd-labs/feat/723-optimization

Improving skip of updateState() by time, and caching dynamics for indexes

contracts/protocol/libraries/logic/ReserveLogic.sol

@@ -98,8 +98,17 @@ library ReserveLogic {
     DataTypes.ReserveData storage reserve,
     DataTypes.ReserveCache memory reserveCache
   ) internal {
+    // If time didn't pass since last stored timestamp, skip state update
+    //solium-disable-next-line
+    if (reserve.lastUpdateTimestamp == uint40(block.timestamp)) {
+      return;
+    }
+
     _updateIndexes(reserve, reserveCache);
     _accrueToTreasury(reserve, reserveCache);
+
+    //solium-disable-next-line
+    reserve.lastUpdateTimestamp = uint40(block.timestamp);
   }
 
   /**
@@ -283,9 +292,6 @@ library ReserveLogic {
     DataTypes.ReserveData storage reserve,
     DataTypes.ReserveCache memory reserveCache
   ) internal {
-    reserveCache.nextLiquidityIndex = reserveCache.currLiquidityIndex;
-    reserveCache.nextVariableBorrowIndex = reserveCache.currVariableBorrowIndex;
-
     // Only cumulating on the supply side if there is any income being produced
     // The case of Reserve Factor 100% is not a problem (currentLiquidityRate == 0),
     // as liquidity index should not be updated
@@ -314,9 +320,6 @@ library ReserveLogic {
       );
       reserve.variableBorrowIndex = reserveCache.nextVariableBorrowIndex.toUint128();
     }
-
-    //solium-disable-next-line
-    reserve.lastUpdateTimestamp = uint40(block.timestamp);
   }
 
   /**
@@ -334,8 +337,9 @@ library ReserveLogic {
 
     reserveCache.reserveConfiguration = reserve.configuration;
     reserveCache.reserveFactor = reserveCache.reserveConfiguration.getReserveFactor();
-    reserveCache.currLiquidityIndex = reserve.liquidityIndex;
-    reserveCache.currVariableBorrowIndex = reserve.variableBorrowIndex;
+    reserveCache.currLiquidityIndex = reserveCache.nextLiquidityIndex = reserve.liquidityIndex;
+    reserveCache.currVariableBorrowIndex = reserveCache.nextVariableBorrowIndex = reserve
+      .variableBorrowIndex;
     reserveCache.currLiquidityRate = reserve.currentLiquidityRate;
     reserveCache.currVariableBorrowRate = reserve.currentVariableBorrowRate;