feat: multiplier nonce.

backed-fi · Oct 1, 2024 · 023e8d1 · 023e8d1
1 parent f538c9a
commit 023e8d1
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Showing 2 changed files with 16 additions and 10 deletions.
diff --git a/contracts/BackedAutoFeeTokenImplementation.sol b/contracts/BackedAutoFeeTokenImplementation.sol
@@ -77,6 +77,8 @@ contract BackedAutoFeeTokenImplementation is BackedTokenImplementation {
 
     uint256 internal _totalShares;
 
+    uint256 public multiplierNonce;
+
     // Events:
 
     /**
@@ -104,10 +106,10 @@ contract BackedAutoFeeTokenImplementation is BackedTokenImplementation {
     // Modifiers:
 
     modifier updateMultiplier() {
-        (uint256 newMultiplier, uint256 periodsPassed) = getCurrentMultiplier();
+        (uint256 newMultiplier, uint256 periodsPassed, uint256 newMultiplierNonce) = getCurrentMultiplier();
         lastTimeFeeApplied = lastTimeFeeApplied + periodLength * periodsPassed;
         if (multiplier != newMultiplier) {
-            _updateMultiplier(newMultiplier);
+            _updateMultiplier(newMultiplier, newMultiplierNonce);
         }
         _;
     }
@@ -155,6 +157,7 @@ contract BackedAutoFeeTokenImplementation is BackedTokenImplementation {
         require(_lastTimeFeeApplied != 0, "Invalid last time fee applied");
 
         multiplier = 1e18;
+        multiplierNonce = 0;
         periodLength = _periodLength;
         lastTimeFeeApplied = _lastTimeFeeApplied;
         feePerPeriod = _feePerPeriod;
@@ -164,7 +167,7 @@ contract BackedAutoFeeTokenImplementation is BackedTokenImplementation {
      * @dev See {IERC20-totalSupply}.
      */
     function totalSupply() public view virtual override returns (uint256) {
-        (uint256 newMultiplier, ) = getCurrentMultiplier();
+        (uint256 newMultiplier, ,) = getCurrentMultiplier();
         return _getUnderlyingAmountByShares(_totalShares, newMultiplier);
     }
 
@@ -174,7 +177,7 @@ contract BackedAutoFeeTokenImplementation is BackedTokenImplementation {
     function balanceOf(
         address account
     ) public view virtual override returns (uint256) {
-        (uint256 newMultiplier, ) = getCurrentMultiplier();
+        (uint256 newMultiplier, ,) = getCurrentMultiplier();
         return _getUnderlyingAmountByShares(sharesOf(account), newMultiplier);
     }
 
@@ -186,13 +189,15 @@ contract BackedAutoFeeTokenImplementation is BackedTokenImplementation {
         public
         view
         virtual
-        returns (uint256 newMultiplier, uint256 periodsPassed)
+        returns (uint256 newMultiplier, uint256 periodsPassed, uint256 newMultiplierNonce)
     {
         periodsPassed = (block.timestamp - lastTimeFeeApplied) / periodLength;
         newMultiplier = multiplier;
+        newMultiplierNonce = multiplierNonce;
         if (feePerPeriod > 0) {
             for (uint256 index = 0; index < periodsPassed; index++) {
                 newMultiplier = (newMultiplier * (1e18 - feePerPeriod)) / 1e18;
+                newMultiplierNonce += 1;
             }
         }
     }
@@ -210,7 +215,7 @@ contract BackedAutoFeeTokenImplementation is BackedTokenImplementation {
     function getSharesByUnderlyingAmount(
         uint256 _underlyingAmount
     ) external view returns (uint256) {
-        (uint256 newMultiplier, ) = getCurrentMultiplier();
+        (uint256 newMultiplier, ,) = getCurrentMultiplier();
         return _getSharesByUnderlyingAmount(_underlyingAmount, newMultiplier);
     }
 
@@ -220,7 +225,7 @@ contract BackedAutoFeeTokenImplementation is BackedTokenImplementation {
     function getUnderlyingAmountByShares(
         uint256 _sharesAmount
     ) external view returns (uint256) {
-        (uint256 newMultiplier, ) = getCurrentMultiplier();
+        (uint256 newMultiplier, ,) = getCurrentMultiplier();
         return _getUnderlyingAmountByShares(_sharesAmount, newMultiplier);
     }
 
@@ -337,7 +342,7 @@ contract BackedAutoFeeTokenImplementation is BackedTokenImplementation {
             multiplier == oldMultiplier,
             "BackedToken: Multiplier changed in the meantime"
         );
-        _updateMultiplier(newMultiplier);
+        _updateMultiplier(newMultiplier, multiplierNonce + 1);
     }
 
     /**
@@ -469,8 +474,9 @@ contract BackedAutoFeeTokenImplementation is BackedTokenImplementation {
      *
      * Emit an {MultiplierUpdated} event.
      */
-    function _updateMultiplier(uint256 newMultiplier) internal virtual {
+    function _updateMultiplier(uint256 newMultiplier, uint256 newMultiplierNonce) internal virtual {
         multiplier = newMultiplier;
+        multiplierNonce = newMultiplierNonce;
         emit MultiplierUpdated(newMultiplier);
     }
 

diff --git a/contracts/BackedTokenImplementation.sol b/contracts/BackedTokenImplementation.sol
@@ -323,5 +323,5 @@ contract BackedTokenImplementation is OwnableUpgradeable, ERC20PermitDelegateTra
      * variables without shifting down storage in the inheritance chain.
      * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
      */
-    uint256[49] private __gap;
+    uint256[48] private __gap;
 }