chore: copy of OptimismMintableERC20.sol

packages/contracts-bedrock/contracts/universal/OptimismMintableUpgradableERC20.sol

@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: MIT
+pragma solidity 0.8.15;
+
+import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import { IERC165 } from "@openzeppelin/contracts/utils/introspection/IERC165.sol";
+import { ILegacyMintableERC20, IOptimismMintableERC20 } from "./IOptimismMintableERC20.sol";
+import { Semver } from "../universal/Semver.sol";
+
+/**
+ * @title OptimismMintableERC20
+ * @notice OptimismMintableERC20 is a standard extension of the base ERC20 token contract designed
+ *         to allow the StandardBridge contracts to mint and burn tokens. This makes it possible to
+ *         use an OptimismMintablERC20 as the L2 representation of an L1 token, or vice-versa.
+ *         Designed to be backwards compatible with the older StandardL2ERC20 token which was only
+ *         meant for use on L2.
+ */
+contract OptimismMintableERC20 is IOptimismMintableERC20, ILegacyMintableERC20, ERC20, Semver {
+    /**
+     * @notice Address of the corresponding version of this token on the remote chain.
+     */
+    address public immutable REMOTE_TOKEN;
+
+    /**
+     * @notice Address of the StandardBridge on this network.
+     */
+    address public immutable BRIDGE;
+
+    /**
+     * @notice Emitted whenever tokens are minted for an account.
+     *
+     * @param account Address of the account tokens are being minted for.
+     * @param amount  Amount of tokens minted.
+     */
+    event Mint(address indexed account, uint256 amount);
+
+    /**
+     * @notice Emitted whenever tokens are burned from an account.
+     *
+     * @param account Address of the account tokens are being burned from.
+     * @param amount  Amount of tokens burned.
+     */
+    event Burn(address indexed account, uint256 amount);
+
+    /**
+     * @notice A modifier that only allows the bridge to call
+     */
+    modifier onlyBridge() {
+        require(msg.sender == BRIDGE, "OptimismMintableERC20: only bridge can mint and burn");
+        _;
+    }
+
+    /**
+     * @custom:semver 1.0.0
+     *
+     * @param _bridge      Address of the L2 standard bridge.
+     * @param _remoteToken Address of the corresponding L1 token.
+     * @param _name        ERC20 name.
+     * @param _symbol      ERC20 symbol.
+     */
+    constructor(
+        address _bridge,
+        address _remoteToken,
+        string memory _name,
+        string memory _symbol
+    ) ERC20(_name, _symbol) Semver(1, 0, 0) {
+        REMOTE_TOKEN = _remoteToken;
+        BRIDGE = _bridge;
+    }
+
+    /**
+     * @notice Allows the StandardBridge on this network to mint tokens.
+     *
+     * @param _to     Address to mint tokens to.
+     * @param _amount Amount of tokens to mint.
+     */
+    function mint(address _to, uint256 _amount)
+        external
+        virtual
+        override(IOptimismMintableERC20, ILegacyMintableERC20)
+        onlyBridge
+    {
+        _mint(_to, _amount);
+        emit Mint(_to, _amount);
+    }
+
+    /**
+     * @notice Allows the StandardBridge on this network to burn tokens.
+     *
+     * @param _from   Address to burn tokens from.
+     * @param _amount Amount of tokens to burn.
+     */
+    function burn(address _from, uint256 _amount)
+        external
+        virtual
+        override(IOptimismMintableERC20, ILegacyMintableERC20)
+        onlyBridge
+    {
+        _burn(_from, _amount);
+        emit Burn(_from, _amount);
+    }
+
+    /**
+     * @notice ERC165 interface check function.
+     *
+     * @param _interfaceId Interface ID to check.
+     *
+     * @return Whether or not the interface is supported by this contract.
+     */
+    function supportsInterface(bytes4 _interfaceId) external pure returns (bool) {
+        bytes4 iface1 = type(IERC165).interfaceId;
+        // Interface corresponding to the legacy L2StandardERC20.
+        bytes4 iface2 = type(ILegacyMintableERC20).interfaceId;
+        // Interface corresponding to the updated OptimismMintableERC20 (this contract).
+        bytes4 iface3 = type(IOptimismMintableERC20).interfaceId;
+        return _interfaceId == iface1 || _interfaceId == iface2 || _interfaceId == iface3;
+    }
+
+    /**
+     * @custom:legacy
+     * @notice Legacy getter for the remote token. Use REMOTE_TOKEN going forward.
+     */
+    function l1Token() public view returns (address) {
+        return REMOTE_TOKEN;
+    }
+
+    /**
+     * @custom:legacy
+     * @notice Legacy getter for the bridge. Use BRIDGE going forward.
+     */
+    function l2Bridge() public view returns (address) {
+        return BRIDGE;
+    }
+
+    /**
+     * @custom:legacy
+     * @notice Legacy getter for REMOTE_TOKEN.
+     */
+    function remoteToken() public view returns (address) {
+        return REMOTE_TOKEN;
+    }
+
+    /**
+     * @custom:legacy
+     * @notice Legacy getter for BRIDGE.
+     */
+    function bridge() public view returns (address) {
+        return BRIDGE;
+    }
+}