Merge pull request #69 from euler-xyz/simplify-getParams

avoid use of assembly in getParams (suggested by @MiloTruck)

Author: hoytech

src/libraries/CtxLib.sol

@@ -19,22 +19,15 @@ library CtxLib {
         }
     }
 
+    error InsufficientCalldata();
+
     /// @dev Unpacks encoded Params from trailing calldata. Loosely based on
     /// the implementation from EIP-3448 (except length is hard-coded).
+    /// 384 is the size of the Params struct after ABI encoding.
     function getParams() internal pure returns (IEulerSwap.Params memory p) {
-        bytes memory data;
-
-        assembly {
-            let size := 384
-            let dataPtr := sub(calldatasize(), size)
-            data := mload(64)
-            // increment free memory pointer by metadata size + 32 bytes (length)
-            mstore(64, add(data, add(size, 32)))
-            mstore(data, size)
-            let memPtr := add(data, 32)
-            calldatacopy(memPtr, dataPtr, size)
+        require(msg.data.length >= 384, InsufficientCalldata());
+        unchecked {
+            return abi.decode(msg.data[msg.data.length - 384:], (IEulerSwap.Params));
         }
-
-        return abi.decode(data, (IEulerSwap.Params));
     }
 }

test/Ctx.t.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 pragma solidity ^0.8.24;
 
-import {EulerSwapTestBase, IEulerSwap} from "./EulerSwapTestBase.t.sol";
+import {EulerSwapTestBase, EulerSwap, IEulerSwap} from "./EulerSwapTestBase.t.sol";
 import {CtxLib} from "../src/libraries/CtxLib.sol";
 
 contract CtxTest is EulerSwapTestBase {
@@ -17,4 +17,32 @@ contract CtxTest is EulerSwapTestBase {
         IEulerSwap.Params memory params = getEulerSwapParams(1e18, 1e18, 1e18, 1e18, 0.4e18, 0.85e18, 0, 0, address(0));
         assertEq(abi.encode(params).length, 384);
     }
+
+    function test_insufficientCalldata() public {
+        // Proxy appends 384 bytes of calldata, so you can't call directly without this
+
+        vm.expectRevert(CtxLib.InsufficientCalldata.selector);
+        EulerSwap(eulerSwapImpl).getParams();
+    }
+
+    function test_callImplementationDirectly() public {
+        // Underlying implementation is locked: must call via a proxy
+
+        bool success;
+
+        vm.expectRevert(EulerSwap.AlreadyActivated.selector);
+        (success,) = eulerSwapImpl.call(
+            padCalldata(
+                abi.encodeCall(EulerSwap.activate, (IEulerSwap.InitialState({currReserve0: 1e18, currReserve1: 1e18})))
+            )
+        );
+
+        vm.expectRevert(EulerSwap.Locked.selector);
+        (success,) = eulerSwapImpl.call(padCalldata(abi.encodeCall(EulerSwap.getReserves, ())));
+    }
+
+    function padCalldata(bytes memory inp) internal pure returns (bytes memory) {
+        IEulerSwap.Params memory params;
+        return abi.encodePacked(inp, abi.encode(params));
+    }
 }

test/FactoryTest.t.sol

@@ -249,14 +249,4 @@ contract FactoryTest is EulerSwapTestBase {
         assertEq(pools.length, 1);
         assertEq(pools[0], hookAddress);
     }
-
-    function testCallImpl() public {
-        // Underlying implementation is locked: must call via a proxy
-
-        vm.expectRevert(EulerSwap.AlreadyActivated.selector);
-        EulerSwap(eulerSwapImpl).activate(IEulerSwap.InitialState({currReserve0: 1e18, currReserve1: 1e18}));
-
-        vm.expectRevert(EulerSwap.Locked.selector);
-        EulerSwap(eulerSwapImpl).getReserves();
-    }
 }