Merge pull request #8 from euler-xyz/getReserves-fn

Feat: expose getReserves() function

Author: hoytech

src/MaglevBase.sol

@@ -17,9 +17,9 @@ abstract contract MaglevBase is IMaglevBase, EVCUtil {
     uint112 public immutable debtLimit1;
     uint256 public immutable feeMultiplier;
 
-    uint112 public reserve0;
-    uint112 public reserve1;
-    uint32 public locked;
+    uint112 internal reserve0;
+    uint112 internal reserve1;
+    uint32 internal locked; // uses single storage slot, accessible via getReserves()
 
     error Locked();
     error Overflow();
@@ -116,6 +116,10 @@ abstract contract MaglevBase is IMaglevBase, EVCUtil {
         }
     }
 
+    function getReserves() public view returns (uint112, uint112, uint32) {
+        return (reserve0, reserve1, locked);
+    }
+
     function quoteExactInput(address tokenIn, address tokenOut, uint256 amountIn) external view returns (uint256) {
         return _computeQuote(tokenIn, tokenOut, amountIn, true);
     }

src/interfaces/IMaglevBase.sol

@@ -15,6 +15,5 @@ interface IMaglevBase {
     function debtLimit0() external view returns (uint112);
     function debtLimit1() external view returns (uint112);
     function feeMultiplier() external view returns (uint256);
-    function reserve0() external view returns (uint112);
-    function reserve1() external view returns (uint112);
+    function getReserves() external view returns (uint112, uint112, uint32);
 }

test/ConstantSum.t.sol

@@ -58,8 +58,9 @@ contract ConstantSumTest is MaglevTestBase {
     }
 
     function test_reserveLimit() public monotonicHolderNAV {
-        assertEq(maglev.reserve0(), 60e18);
-        assertEq(maglev.reserve1(), 60e18);
+        (uint112 reserve0, uint112 reserve1,) = maglev.getReserves();
+        assertEq(reserve0, 60e18);
+        assertEq(reserve1, 60e18);
 
         assetTST.mint(address(this), 1000e18);
 
@@ -80,38 +81,48 @@ contract ConstantSumTest is MaglevTestBase {
             maglev.swap(0, amount, address(this), "");
         }
 
+        (reserve0, reserve1,) = maglev.getReserves();
+
         assertEq(eTST.balanceOf(holder), 70e18);
         assertEq(eTST2.debtOf(holder), 50e18);
-        assertEq(maglev.reserve0(), 120e18);
-        assertEq(maglev.reserve1(), 0e18);
+        assertEq(reserve0, 120e18);
+        assertEq(reserve1, 0e18);
 
         // Same debt limit means reserves not affected
 
         createMaglev(50e18, 50e18, 0, 1, 1);
 
-        assertEq(maglev.reserve0(), 120e18);
-        assertEq(maglev.reserve1(), 0e18);
+        (reserve0, reserve1,) = maglev.getReserves();
+
+        assertEq(reserve0, 120e18);
+        assertEq(reserve1, 0e18);
 
         // Increase debt limit on one side
 
         createMaglev(50e18, 55e18, 0, 1, 1);
 
-        assertEq(maglev.reserve0(), 120e18);
-        assertEq(maglev.reserve1(), 5e18);
+        (reserve0, reserve1,) = maglev.getReserves();
+
+        assertEq(reserve0, 120e18);
+        assertEq(reserve1, 5e18);
 
         // And the other
 
         createMaglev(55e18, 55e18, 0, 1, 1);
 
-        assertEq(maglev.reserve0(), 125e18);
-        assertEq(maglev.reserve1(), 5e18);
+        (reserve0, reserve1,) = maglev.getReserves();
+
+        assertEq(reserve0, 125e18);
+        assertEq(reserve1, 5e18);
 
         // Shrink debt limit
 
         createMaglev(40e18, 45e18, 0, 1, 1);
 
-        assertEq(maglev.reserve0(), 110e18);
-        assertEq(maglev.reserve1(), 0e18); // can't go below 0
+        (reserve0, reserve1,) = maglev.getReserves();
+
+        assertEq(reserve0, 110e18);
+        assertEq(reserve1, 0e18); // can't go below 0
     }
 
     function test_basicSwapFuzz(uint256 amount1, uint256 amount2) public monotonicHolderNAV {

test/MaglevTestBase.t.sol

@@ -91,14 +91,16 @@ contract MaglevTestBase is EVaultTestBase {
     }
 
     function logState(address ml) internal view {
+        (uint112 reserve0, uint112 reserve1,) = MaglevBase(ml).getReserves();
+
         console.log("--------------------");
         console.log("Account States:");
         console.log("HOLDER");
         console.log("  eTST Vault assets:  ", eTST.convertToAssets(eTST.balanceOf(holder)));
         console.log("  eTST Vault debt:    ", eTST.debtOf(holder));
         console.log("  eTST2 Vault assets: ", eTST2.convertToAssets(eTST2.balanceOf(holder)));
         console.log("  eTST2 Vault debt:   ", eTST2.debtOf(holder));
-        console.log("  reserve0:           ", MaglevBase(ml).reserve0());
-        console.log("  reserve1:           ", MaglevBase(ml).reserve1());
+        console.log("  reserve0:           ", reserve0);
+        console.log("  reserve1:           ", reserve1);
     }
 }