Merge branch 'main' into 3070/add-is-winer-to-solver-competition-endp…

…oint

crates/contracts/artifacts/Spardose.json

@@ -0,0 +1 @@
+{"abi":[{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"requestFunds","outputs":[],"stateMutability":"nonpayable","type":"function"}],"bytecode":"0x608060405234801561001057600080fd5b506102de806100206000396000f3fe608060405234801561001057600080fd5b506004361061002b5760003560e01c8063494666b614610030575b600080fd5b61004361003e36600461023b565b610045565b005b61006673ffffffffffffffffffffffffffffffffffffffff8316338361006a565b5050565b6040805173ffffffffffffffffffffffffffffffffffffffff848116602483015260448083018590528351808403909101815260649092019092526020810180517bffffffffffffffffffffffffffffffffffffffffffffffffffffffff167fa9059cbb00000000000000000000000000000000000000000000000000000000179052906000906100fd90861683610179565b90506101088161018e565b610172576040517f08c379a000000000000000000000000000000000000000000000000000000000815260206004820152601a60248201527f5361666545524332303a207472616e73666572206661696c6564000000000000604482015260640160405180910390fd5b5050505050565b6060610187836000846101b5565b9392505050565b60008151600014806101af5750818060200190518101906101af9190610280565b92915050565b606060008473ffffffffffffffffffffffffffffffffffffffff1684846040516101df91906102a2565b60006040518083038185875af1925050503d806000811461021c576040519150601f19603f3d011682016040523d82523d6000602084013e610221565b606091505b50925090508061023357815160208301fd5b509392505050565b6000806040838503121561024e57600080fd5b823573ffffffffffffffffffffffffffffffffffffffff8116811461027257600080fd5b946020939093013593505050565b60006020828403121561029257600080fd5b8151801515811461018757600080fd5b6000825160005b818110156102c357602081860181015185830152016102a9565b50600092019182525091905056fea164736f6c6343000811000a","deployedBytecode":"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","devdoc":{"methods":{}},"userdoc":{"methods":{}}}

crates/contracts/build.rs

@@ -990,8 +990,9 @@ fn main() {
     generate_contract("CowAmmUniswapV2PriceOracle");
 
     // Support contracts used for trade and token simulations.
-    generate_contract("Trader");
     generate_contract("Solver");
+    generate_contract("Spardose");
+    generate_contract("Trader");
 
     // Support contracts used for various order simulations.
     generate_contract("Balances");

crates/contracts/solidity/Makefile

@@ -14,6 +14,7 @@ CONTRACTS := \
 	Signatures.sol \
 	SimulateCode.sol \
 	Solver.sol \
+	Spardose.sol \
 	Swapper.sol \
 	Trader.sol
 ARTIFACTS := $(patsubst %.sol,$(ARTIFACTDIR)/%.json,$(CONTRACTS))

crates/contracts/solidity/Solver.sol

@@ -16,7 +16,11 @@ import { Trader } from "./Trader.sol";
 contract Solver {
     using Caller for *;
     using Math for *;
-    using SafeERC20 for *;
+
+    struct Mock {
+        bool enabled;
+        address spardose;
+    }
 
     uint256 private _simulationOverhead;
     uint256[] private _queriedBalances;
@@ -35,10 +39,10 @@ contract Solver {
     /// @param tokens - list of tokens used in the trade
     /// @param receiver - address receiving the bought tokens
     /// @param settlementCall - the calldata of the `settle()` call
-    /// @param mockPreconditions - controls whether things like ETH wrapping
-    ///            or setting allowance should be done on behalf of the
-    ///            user to support quote verification even if the user didn't
-    ///            wrap their ETH or set the necessary allowances yet.
+    /// @param mock - mocking configuration for the simulation; this controls
+    ///             whether things like ETH wrapping, setting allowance and
+    ///             pre-funding should be done on behalf of the user to support
+    ///             quote verification for users who aren't ready to swap.
     ///
     /// @return gasUsed - gas used for the `settle()` call
     /// @return queriedBalances - list of balances stored during the simulation
@@ -51,30 +55,34 @@ contract Solver {
         address[] calldata tokens,
         address payable receiver,
         bytes calldata settlementCall,
-        bool mockPreconditions
+        Mock memory mock
     ) external returns (
         uint256 gasUsed,
         uint256[] memory queriedBalances
     ) {
         require(msg.sender == address(this), "only simulation logic is allowed to call 'swap' function");
 
-        // Prepare the trade in the context of the trader so we are allowed
-        // to set approvals and things like that.
-        if (mockPreconditions) {
+        if (mock.enabled) {
+            // Prepare the trade in the context of the trader so we are allowed
+            // to set approvals and things like that.
             Trader(trader)
                 .prepareSwap(
                     settlementContract,
                     sellToken,
                     sellAmount,
-                    nativeToken
+                    nativeToken,
+                    mock.spardose
                 );
         }
 
         // Warm the storage for sending ETH to smart contract addresses.
         // We allow this call to revert becaues it was either unnecessary in the first place
         // or failing to send `ETH` to the `receiver` will cause a revert in the settlement
         // contract.
-        receiver.call{value: 0}("");
+        {
+            (bool success,) = receiver.call{value: 0}("");
+            success;
+        }
 
         // Store pre-settlement balances
         _storeSettlementBalances(tokens, settlementContract);

crates/contracts/solidity/Spardose.sol

@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.17;
+
+import { IERC20 } from "./interfaces/IERC20.sol";
+import { SafeERC20 } from "./libraries/SafeERC20.sol";
+
+/// @title A piggy bank contract (Spardose is piggy bank in German)
+/// @notice This contract account is used for pre-funding traders with tokens
+/// for quote simulations. A separate contract is used (instead of overriding
+/// the balance of the solver or trader directly) in order to interfere as
+/// little as possible with the settlement.
+contract Spardose {
+    using SafeERC20 for *;
+
+    /// @dev Request funds from the piggy bank to be transferred to the caller.
+    /// Reverts if the transfer fails.
+    ///
+    /// @param token - the token request funds for
+    /// @param amount - the amount of `token` to transfer
+    function requestFunds(address token, uint256 amount) external {
+        IERC20(token).safeTransfer(msg.sender, amount);
+    }
+}

crates/contracts/solidity/Trader.sol

@@ -6,6 +6,7 @@ import { Interaction, Trade, ISettlement } from "./interfaces/ISettlement.sol";
 import { Caller } from "./libraries/Caller.sol";
 import { Math } from "./libraries/Math.sol";
 import { SafeERC20 } from "./libraries/SafeERC20.sol";
+import { Spardose } from "./Spardose.sol";
 
 /// @title A contract for impersonating a trader.
 contract Trader {
@@ -62,29 +63,36 @@ contract Trader {
     receive() external payable {}
 
     /// @dev Executes needed actions on behalf of the trader to make the trade possible.
-    ///      (e.g. wrapping ETH and setting approvals)
+    ///      (e.g. wrapping ETH, setting approvals, and funding the account)
     /// @param settlementContract - pass in settlement contract because it does not have
     /// a stable address in tests.
     /// @param sellToken - token being sold by the trade
     /// @param sellAmount - expected amount to be sold according to the quote
     /// @param nativeToken - ERC20 version of the chain's native token
+    /// @param spardose - piggy bank for requesting additional funds
     function prepareSwap(
         ISettlement settlementContract,
         address sellToken,
         uint256 sellAmount,
-        address nativeToken
+        address nativeToken,
+        address spardose
     ) external {
         require(!alreadyCalled(), "prepareSwap can only be called once");
 
         if (sellToken == nativeToken) {
             uint256 availableNativeToken = IERC20(sellToken).balanceOf(address(this));
             if (availableNativeToken < sellAmount) {
                 uint256 amountToWrap = sellAmount - availableNativeToken;
-                require(address(this).balance >= amountToWrap, "not enough ETH to wrap");
-                // Simulate wrapping the missing `ETH` so the user doesn't have to spend gas
-                // on that just to get a quote. If they are happy with the quote and want to
-                // create an order they will actually have to do the wrapping, though.
-                INativeERC20(nativeToken).deposit{value: amountToWrap}();
+                // If the user has sufficient balance, simulate the wrapping the missing
+                // `ETH` so the user doesn't have to spend gas on that just to get a quote.
+                // If they are happy with the quote and want to create an order they will
+                // actually have to do the wrapping, though. Note that we don't attempt to
+                // wrap if the user doesn't have sufficient `ETH` balance, since that would
+                // revert. Instead, we fall-through so that we handle insufficient sell
+                // token balances uniformly for all tokens.
+                if (address(this).balance >= amountToWrap) {
+                    INativeERC20(nativeToken).deposit{value: amountToWrap}();
+                }
             }
         }
 
@@ -100,8 +108,19 @@ contract Trader {
             IERC20(sellToken).safeApprove(address(settlementContract.vaultRelayer()), type(uint256).max);
         }
 
-        uint256 availableSellToken = IERC20(sellToken).balanceOf(address(this));
-        require(availableSellToken >= sellAmount, "trader does not have enough sell_token");
+        // Ensure that the user has sufficient sell token balance. If not, request some
+        // funds from the Spardose (piggy bank) which will be available if balance
+        // overrides are enabled.
+        uint256 sellBalance = IERC20(sellToken).balanceOf(address(this));
+        if (sellBalance < sellAmount) {
+            try Spardose(spardose).requestFunds(sellToken, sellAmount - sellBalance) {}
+            catch {
+                // The trader does not have sufficient sell token balance, and the
+                // piggy bank pre-fund failed, as balance overrides are not available.
+                // Revert with a helpful message.
+                revert("trader does not have enough sell token");
+            }
+        }
     }
 
     /// @dev Validate all signature requests. This makes "signing" CoW protocol

crates/contracts/solidity/libraries/SafeERC20.sol

@@ -7,13 +7,19 @@ import { Caller } from "./Caller.sol";
 library SafeERC20 {
     using Caller for *;
 
+    function safeTransfer(IERC20 self, address target, uint256 amount) internal {
+        bytes memory cdata = abi.encodeCall(self.transfer, (target, amount));
+        bytes memory rdata = address(self).doCall(cdata);
+        require(check(rdata), "SafeERC20: transfer failed");
+    }
+
     function safeApprove(IERC20 self, address target, uint256 amount) internal {
         bytes memory cdata = abi.encodeCall(self.approve, (target, amount));
         bytes memory rdata = address(self).doCall(cdata);
-        check(rdata, "SafeERC20: approval failed");
+        require(check(rdata), "SafeERC20: approval failed");
     }
 
-    function check(bytes memory self, string memory message) internal pure {
-        require(self.length == 0 || abi.decode(self, (bool)), message);
+    function check(bytes memory rdata) internal pure returns (bool ok) {
+        return rdata.length == 0 || abi.decode(rdata, (bool));
     }
 }

crates/contracts/src/lib.rs

@@ -114,6 +114,7 @@ pub mod support {
         Signatures;
         SimulateCode;
         Solver;
+        Spardose;
         Swapper;
         Trader;
     }