Add stETH wrap/unwrap support [TKR-377] (#476)

* Update MixinLido to support stETH wrapping/unwrapping

* Update LidoSampler and asset-swapper

* Re-use token address constants in LIDO_INFO_BY_CHAIN

* Update CHANGELOG.json

* Add stETH <-> wstETH to TokenAdjacencyGraph

* Change lido gas schedule code style

* Move allowance approval inside the wrap branch

* Refactor LidoSampler to reduce its bytecode size

contracts/zero-ex/CHANGELOG.json

@@ -5,6 +5,10 @@
             {
                 "note": "Splits BridgeAdapter up by chain",
                 "pr": 487
+            },
+            {
+                "note": "Add stETH wrap/unwrap support",
+                "pr": 476
             }
         ]
     },

contracts/zero-ex/contracts/src/transformers/bridges/mixins/MixinLido.sol

@@ -26,7 +26,7 @@ import "@0x/contracts-erc20/contracts/src/v06/IEtherTokenV06.sol";
 
 
 /// @dev Minimal interface for minting StETH
-interface ILido {
+interface IStETH {
     /// @dev Adds eth to the pool
     /// @param _referral optional address for referrals
     /// @return StETH Amount of shares generated
@@ -37,6 +37,33 @@ interface ILido {
     function getPooledEthByShares(uint256 _sharesAmount) external view returns (uint256);
 }
 
+/// @dev Minimal interface for wrapping/unwrapping stETH.
+interface IWstETH {
+
+    /**
+     * @notice Exchanges stETH to wstETH
+     * @param _stETHAmount amount of stETH to wrap in exchange for wstETH
+     * @dev Requirements:
+     *  - `_stETHAmount` must be non-zero
+     *  - msg.sender must approve at least `_stETHAmount` stETH to this
+     *    contract.
+     *  - msg.sender must have at least `_stETHAmount` of stETH.
+     * User should first approve _stETHAmount to the WstETH contract
+     * @return Amount of wstETH user receives after wrap
+     */
+    function wrap(uint256 _stETHAmount) external returns (uint256);
+
+    /**
+     * @notice Exchanges wstETH to stETH
+     * @param _wstETHAmount amount of wstETH to uwrap in exchange for stETH
+     * @dev Requirements:
+     *  - `_wstETHAmount` must be non-zero
+     *  - msg.sender must have at least `_wstETHAmount` wstETH.
+     * @return Amount of stETH user receives after unwrap
+     */
+    function unwrap(uint256 _wstETHAmount) external returns (uint256);
+}
+
 
 contract MixinLido {
     using LibERC20TokenV06 for IERC20TokenV06;
@@ -59,12 +86,43 @@ contract MixinLido {
         internal
         returns (uint256 boughtAmount)
     {
-        (ILido lido) = abi.decode(bridgeData, (ILido));
-        if (address(sellToken) == address(WETH) && address(buyToken) == address(lido)) {
+        if (address(sellToken) == address(WETH)) {
+            return _tradeStETH(buyToken, sellAmount, bridgeData);
+        } 
+
+        return _tradeWstETH(sellToken, buyToken, sellAmount, bridgeData);
+    }
+
+    function _tradeStETH(
+        IERC20TokenV06 buyToken,
+        uint256 sellAmount,
+        bytes memory bridgeData
+    ) private returns (uint256 boughtAmount) {
+        (IStETH stETH) = abi.decode(bridgeData, (IStETH));
+        if (address(buyToken) == address(stETH)) {
             WETH.withdraw(sellAmount);
-            boughtAmount = lido.getPooledEthByShares(lido.submit{ value: sellAmount}(address(0)));
-        } else {
-            revert("MixinLido/UNSUPPORTED_TOKEN_PAIR");
+            return stETH.getPooledEthByShares(stETH.submit{ value: sellAmount}(address(0)));
         }
+
+        revert("MixinLido/UNSUPPORTED_TOKEN_PAIR");
+    }
+
+    function _tradeWstETH(
+        IERC20TokenV06 sellToken,
+        IERC20TokenV06 buyToken,
+        uint256 sellAmount,
+        bytes memory bridgeData
+
+    ) private returns(uint256 boughtAmount){
+        (IEtherTokenV06 stETH, IWstETH wstETH) = abi.decode(bridgeData, (IEtherTokenV06, IWstETH));
+        if (address(sellToken) == address(stETH) && address(buyToken) == address(wstETH) ) {
+            sellToken.approveIfBelow(address(wstETH), sellAmount);
+            return wstETH.wrap(sellAmount);
+        }
+        if (address(sellToken) == address(wstETH) && address(buyToken) == address(stETH) ) {
+            return wstETH.unwrap(sellAmount);
+        }
+
+        revert("MixinLido/UNSUPPORTED_TOKEN_PAIR");
     }
 }

packages/asset-swapper/CHANGELOG.json

@@ -2,6 +2,10 @@
     {
         "version": "16.61.0",
         "changes": [
+            {
+                "note": "Add stETH wrap/unwrap support",
+                "pr": 476
+            },
             {
                 "note": "Offboard/clean up Oasis, CoFix, and legacy Kyber",
                 "pr": 482

packages/asset-swapper/src/utils/market_operation_utils/constants.ts

@@ -22,6 +22,7 @@ import {
 <<<<<<< HEAD
 =======
     isFinalUniswapV3FillData,
+    LidoFillData,
     LidoInfo,
     LiquidityProviderFillData,
     LiquidityProviderRegistry,
@@ -428,6 +429,7 @@ export const MAINNET_TOKENS = {
     sEUR: '0xd71ecff9342a5ced620049e616c5035f1db98620',
     sETH: '0x5e74c9036fb86bd7ecdcb084a0673efc32ea31cb',
     stETH: '0xae7ab96520de3a18e5e111b5eaab095312d7fe84',
+    wstETH: '0x7f39c581f595b53c5cb19bd0b3f8da6c935e2ca0',
     LINK: '0x514910771af9ca656af840dff83e8264ecf986ca',
     MANA: '0x0f5d2fb29fb7d3cfee444a200298f468908cc942',
     KNC: '0xdefa4e8a7bcba345f687a2f1456f5edd9ce97202',
@@ -916,6 +918,10 @@ export const DEFAULT_TOKEN_ADJACENCY_GRAPH_BY_CHAIN_ID = valueByChainId<TokenAdj
                 builder
                     .add(MAINNET_TOKENS.OHMV2, MAINNET_TOKENS.BTRFLY)
                     .add(MAINNET_TOKENS.BTRFLY, MAINNET_TOKENS.OHMV2);
+                // Lido
+                builder
+                    .add(MAINNET_TOKENS.stETH, MAINNET_TOKENS.wstETH)
+                    .add(MAINNET_TOKENS.wstETH, MAINNET_TOKENS.stETH);
             })
             // Build
             .build(),
@@ -2112,11 +2118,13 @@ export const BEETHOVEN_X_VAULT_ADDRESS_BY_CHAIN = valueByChainId<string>(
 export const LIDO_INFO_BY_CHAIN = valueByChainId<LidoInfo>(
     {
         [ChainId.Mainnet]: {
-            stEthToken: '0xae7ab96520de3a18e5e111b5eaab095312d7fe84',
+            stEthToken: MAINNET_TOKENS.stETH,
+            wstEthToken: MAINNET_TOKENS.wstETH,
             wethToken: MAINNET_TOKENS.WETH,
         },
     },
     {
+        wstEthToken: NULL_ADDRESS,
         stEthToken: NULL_ADDRESS,
         wethToken: NULL_ADDRESS,
     },
@@ -2511,7 +2519,18 @@ export const DEFAULT_GAS_SCHEDULE: Required<FeeSchedule> = {
 
         return gas;
     },
-    [ERC20BridgeSource.Lido]: () => 226e3,
+    [ERC20BridgeSource.Lido]: (fillData?: FillData) => {
+        const lidoFillData = fillData as LidoFillData;
+        const wethAddress = NATIVE_FEE_TOKEN_BY_CHAIN_ID[ChainId.Mainnet];
+        // WETH -> stETH
+        if (lidoFillData.takerToken === wethAddress) {
+            return 226e3;
+        } else if (lidoFillData.takerToken === lidoFillData.stEthTokenAddress) {
+            return 120e3;
+        } else {
+            return 95e3;
+        }
+    },
     [ERC20BridgeSource.AaveV2]: (fillData?: FillData) => {
         const aaveFillData = fillData as AaveV2FillData;
         // NOTE: The Aave deposit method is more expensive than the withdraw

packages/asset-swapper/src/utils/market_operation_utils/orders.ts

@@ -322,7 +322,7 @@ export function createBridgeDataForBridgeOrder(order: OptimizedMarketBridgeOrder
             break;
         case ERC20BridgeSource.Lido:
             const lidoFillData = (order as OptimizedMarketBridgeOrder<LidoFillData>).fillData;
-            bridgeData = encoder.encode([lidoFillData.stEthTokenAddress]);
+            bridgeData = encoder.encode([lidoFillData.stEthTokenAddress, lidoFillData.wstEthTokenAddress]);
             break;
         case ERC20BridgeSource.AaveV2:
             const aaveFillData = (order as OptimizedMarketBridgeOrder<AaveV2FillData>).fillData;
@@ -507,7 +507,7 @@ export const BRIDGE_ENCODERS: {
         { name: 'path', type: 'bytes' },
     ]),
     [ERC20BridgeSource.KyberDmm]: AbiEncoder.create('(address,address[],address[])'),
-    [ERC20BridgeSource.Lido]: AbiEncoder.create('(address)'),
+    [ERC20BridgeSource.Lido]: AbiEncoder.create('(address,address)'),
     [ERC20BridgeSource.AaveV2]: AbiEncoder.create('(address,address)'),
     [ERC20BridgeSource.Compound]: AbiEncoder.create('(address)'),
     [ERC20BridgeSource.Geist]: AbiEncoder.create('(address,address)'),

packages/asset-swapper/src/utils/market_operation_utils/sampler_operations.ts

@@ -1106,8 +1106,10 @@ export class SamplerOperations {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.Lido,
             fillData: {
+                makerToken,
                 takerToken,
                 stEthTokenAddress: lidoInfo.stEthToken,
+                wstEthTokenAddress: lidoInfo.wstEthToken,
             },
             contract: this._samplerContract,
             function: this._samplerContract.sampleSellsFromLido,
@@ -1124,8 +1126,10 @@ export class SamplerOperations {
         return new SamplerContractOperation({
             source: ERC20BridgeSource.Lido,
             fillData: {
+                makerToken,
                 takerToken,
                 stEthTokenAddress: lidoInfo.stEthToken,
+                wstEthTokenAddress: lidoInfo.wstEthToken,
             },
             contract: this._samplerContract,
             function: this._samplerContract.sampleBuysFromLido,
@@ -1603,16 +1607,10 @@ export class SamplerOperations {
                         ].map(path => this.getUniswapV3SellQuotes(router, quoter, path, takerFillAmounts));
                     }
                     case ERC20BridgeSource.Lido: {
-                        const lidoInfo = LIDO_INFO_BY_CHAIN[this.chainId];
-                        if (
-                            lidoInfo.stEthToken === NULL_ADDRESS ||
-                            lidoInfo.wethToken === NULL_ADDRESS ||
-                            takerToken.toLowerCase() !== lidoInfo.wethToken.toLowerCase() ||
-                            makerToken.toLowerCase() !== lidoInfo.stEthToken.toLowerCase()
-                        ) {
+                        if (!this._isLidoSupported(takerToken, makerToken)) {
                             return [];
                         }
-
+                        const lidoInfo = LIDO_INFO_BY_CHAIN[this.chainId];
                         return this.getLidoSellQuotes(lidoInfo, makerToken, takerToken, takerFillAmounts);
                     }
                     case ERC20BridgeSource.AaveV2: {
@@ -1685,6 +1683,24 @@ export class SamplerOperations {
         return allOps;
     }
 
+    private _isLidoSupported(takerTokenAddress: string, makerTokenAddress: string): boolean {
+        const lidoInfo = LIDO_INFO_BY_CHAIN[this.chainId];
+        if (lidoInfo.wethToken === NULL_ADDRESS) {
+            return false;
+        }
+        const takerToken = takerTokenAddress.toLowerCase();
+        const makerToken = makerTokenAddress.toLowerCase();
+        const wethToken = lidoInfo.wethToken.toLowerCase();
+        const stEthToken = lidoInfo.stEthToken.toLowerCase();
+        const wstEthToken = lidoInfo.wstEthToken.toLowerCase();
+
+        if (takerToken === wethToken && makerToken === stEthToken) {
+            return true;
+        }
+
+        return _.difference([stEthToken, wstEthToken], [takerToken, makerToken]).length === 0;
+    }
+
     private _getBuyQuoteOperations(
         sources: ERC20BridgeSource[],
         makerToken: string,
@@ -1924,17 +1940,10 @@ export class SamplerOperations {
                         ].map(path => this.getUniswapV3BuyQuotes(router, quoter, path, makerFillAmounts));
                     }
                     case ERC20BridgeSource.Lido: {
-                        const lidoInfo = LIDO_INFO_BY_CHAIN[this.chainId];
-
-                        if (
-                            lidoInfo.stEthToken === NULL_ADDRESS ||
-                            lidoInfo.wethToken === NULL_ADDRESS ||
-                            takerToken.toLowerCase() !== lidoInfo.wethToken.toLowerCase() ||
-                            makerToken.toLowerCase() !== lidoInfo.stEthToken.toLowerCase()
-                        ) {
+                        if (!this._isLidoSupported(takerToken, makerToken)) {
                             return [];
                         }
-
+                        const lidoInfo = LIDO_INFO_BY_CHAIN[this.chainId];
                         return this.getLidoBuyQuotes(lidoInfo, makerToken, takerToken, makerFillAmounts);
                     }
                     case ERC20BridgeSource.AaveV2: {

packages/asset-swapper/src/utils/market_operation_utils/types.ts

@@ -174,6 +174,7 @@ export interface PsmInfo {
 export interface LidoInfo {
     stEthToken: string;
     wethToken: string;
+    wstEthToken: string;
 }
 
 /**
@@ -312,8 +313,16 @@ export interface UniswapV3FillData extends BridgeFillData {
     encodedPath: Bytes;
 }
 
+<<<<<<< HEAD
 export interface LiquidityProviderFillData extends BridgeFillData {
     poolAddress: Address;
+=======
+export interface LidoFillData extends FillData {
+    stEthTokenAddress: string;
+    wstEthTokenAddress: string;
+    takerToken: string;
+    makerToken: string;
+>>>>>>> db76da58d (Add stETH wrap/unwrap support [TKR-377] (#476))
 }
 
 export interface CurveFillData extends BridgeFillData {
@@ -370,7 +379,7 @@ export interface Fill {
     input: BigNumber;
     // Output fill amount (maker asset amount in a sell, taker asset amount in a buy).
     output: BigNumber;
-    // The output fill amount, ajdusted by fees.
+    // The output fill amount, adjusted by fees.
     adjustedOutput: BigNumber;
     // Fill that must precede this one. This enforces certain fills to be contiguous.
     parent?: Fill;