refactor: use BurnMintErc20 everywhere

Author: prestwich

src/apps/Bridge.sol

@@ -2,25 +2,20 @@
 pragma solidity ^0.8.13;
 
 import {RollupOrders} from "zenith/src/orders/RollupOrders.sol";
-import {SimpleERC20} from "simple-erc20/SimpleERC20.sol";
+import {BurnMintERC20} from "../vendor/BurnMintERC20.sol";
 
 import {SignetL2} from "../l2/Signet.sol";
 
-abstract contract BridgeL2 is SignetL2, SimpleERC20 {
+abstract contract BridgeL2 is SignetL2, BurnMintERC20 {
     /// @notice The address of the asset on the host chain.
     address immutable HOST_ASSET;
     /// @notice The address of the bank on the host chain. The bank holds the
     ///         asset while tokens are bridged into the rollup.
     address immutable HOST_BANK;
 
-    constructor(
-        address _hostAsset,
-        address _hostBank,
-        address _initialOwner,
-        string memory _name,
-        string memory _symbol,
-        uint8 _decimals
-    ) SimpleERC20(_initialOwner, _name, _symbol, _decimals) {
+    constructor(address _hostAsset, address _hostBank, string memory _name, string memory _symbol, uint8 _decimals)
+        BurnMintERC20(_name, _symbol, _decimals, 0, 0)
+    {
         HOST_ASSET = _hostAsset;
         HOST_BANK = _hostBank;
     }

src/apps/Lido.sol

@@ -5,8 +5,7 @@ import {RollupOrders} from "zenith/src/orders/RollupOrders.sol";
 import {SafeERC20} from "openzeppelin-contracts/contracts/token/ERC20/utils/SafeERC20.sol";
 import {IERC20} from "openzeppelin-contracts/contracts/token/ERC20/IERC20.sol";
 
-import {SignetL2} from "../l2/Signet.sol";
-import {BurnMintERC20} from "../vendor/BurnMintERC20.sol";
+import {BridgeL2} from "./Bridge.sol";
 
 /// @notice An example contract, implementing LIDO staking from Signet L2, with
 /// support for CCIP teleporting.
@@ -23,47 +22,17 @@ import {BurnMintERC20} from "../vendor/BurnMintERC20.sol";
 ///   WETH to wstETH on L1 and delivers it to `HOST_PASSAGE`, and mints stETH
 ///   on L2 to `recipient`.
 ///
-contract LidoL2 is SignetL2, BurnMintERC20 {
+contract LidoL2 is BridgeL2 {
     using SafeERC20 for IERC20;
 
     /// @notice The WstETH token on the host.
     address public immutable HOST_WSTETH;
 
-    constructor(address _hostWsteth) BurnMintERC20("Signet Lido Staked Ether", "stETH", 18, 0, 0) {
+    constructor(address _hostWsteth) BridgeL2(_hostWsteth, HOST_PASSAGE, "Lido Staked Ether", "stETH", 18) {
         HOST_WSTETH = _hostWsteth;
         WETH.forceApprove(address(ORDERS), type(uint256).max);
     }
 
-    /// @notice Create an order to bridge in wstETH from L1, and mint stETH on
-    /// L2.
-    function _bridgeIn(address recipient, uint256 amount, RollupOrders.Input[] memory inputs) internal {
-        RollupOrders.Output[] memory outputs = new RollupOrders.Output[](1);
-        outputs[0] = makeHostOutput(HOST_WSTETH, amount, address(HOST_PASSAGE));
-
-        ORDERS.initiate(block.timestamp, inputs, outputs);
-
-        _mint(recipient, amount);
-    }
-
-    /// @notice Bridge in wstETH from L1, and mint stETH on L2.
-    function bridgeIn(address recipient, uint256 amount) external {
-        _bridgeIn(recipient, amount, new RollupOrders.Input[](0));
-    }
-
-    /// @notice Burn stETH on L2, and create an order to bridge out wstETH to
-    /// L1. If the order is not filled, the stETH will not be burned.
-    ///
-    /// This transaction should be paired with some off-chain logic that fills
-    /// orders from the L1 bank.
-    function bridgeOut(address recipient, uint256 amount) public {
-        _burn(msg.sender, amount);
-
-        RollupOrders.Output[] memory outputs = new RollupOrders.Output[](1);
-        outputs[0] = makeHostOutput(HOST_WSTETH, amount, recipient);
-
-        ORDERS.initiate(block.timestamp, new RollupOrders.Input[](0), outputs);
-    }
-
     /// @notice Transfer WETH from `funder`, create an order to convert it to
     /// wstETH on L1 and bridge it to L2, and mint stETH to `recipient`.
     function enter(address funder, uint256 amountIn, address recipient, uint256 amountOut) external {

src/apps/SignetCoreAsset.sol

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.13;
+
+import {BridgeL2} from "./Bridge.sol";
+
+contract SignetCoreAsset is BridgeL2 {
+    constructor(
+        address _hostAsset,
+        address _hostPassageAdmin,
+        string memory _name,
+        string memory _symbol,
+        uint8 _decimals
+    ) BridgeL2(_hostAsset, HOST_PASSAGE, _name, _symbol, _decimals) {
+        _revokeRole(DEFAULT_ADMIN_ROLE, msg.sender);
+        _grantRole(DEFAULT_ADMIN_ROLE, _hostPassageAdmin);
+        _grantRole(MINTER_ROLE, TOKEN_MINTER);
+    }
+}

src/l2/Signet.sol

@@ -12,6 +12,9 @@ contract SignetL2 {
     /// @notice Sentinal value for the native asset in order inputs/outputs
     address constant NATIVE_ASSET = address(0);
 
+    /// @notice System address that produces System minted tokens.
+    address constant TOKEN_MINTER = 0x00000000000000000000746f6b656E61646d696E;
+
     /// @notice The chain ID of the host network.
     uint32 internal immutable HOST_CHAIN_ID;