arb gateway contracts and restructure

.nvmrc

@@ -1 +1 @@
-12
+16

.travis.yml

@@ -2,7 +2,7 @@ dist: trusty
 sudo: required
 language: node_js
 node_js:
-  - '12'
+  - '16'
 cache:
   directories:
     - node_modules

contracts/_interfaces/bridge-gateways/IArbitrumGateway.sol

@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+import {IBCRebaseGatewayEvents, ISCRebaseGatewayEvents, ITransferGatewayEvents} from "./IGateway.sol";
+import {ITokenGateway} from "arb-bridge-peripherals/contracts/tokenbridge/libraries/gateway/ITokenGateway.sol";
+
+// Arbitrum chains expect the cross chain transaction to "pre-pay" in eth
+// for execution on the other chain
+// https://developer.offchainlabs.com/docs/l1_l2_messages
+
+interface IArbitrumBCRebaseGateway is IBCRebaseGatewayEvents {
+    event RebaseReportInitiated(uint256 indexed _sequenceNumber);
+
+    function reportRebaseInit(
+        uint256 _maxSubmissionCost,
+        uint256 _maxGas,
+        uint256 _gasPriceBid
+    ) external payable returns (bytes memory);
+}
+
+interface IArbitrumSCRebaseGateway is ISCRebaseGatewayEvents {
+    event RebaseReportFinalized(uint256 indexed _exitNum);
+
+    function reportRebaseCommit(uint256 globalAmpleforthEpoch, uint256 globalAMPLSupply) external;
+}
+
+interface IArbitrumTransferGateway is ITransferGatewayEvents, ITokenGateway {
+    function getOutboundCalldata(
+        address _l1Token,
+        address _from,
+        address _to,
+        uint256 _amount,
+        bytes memory _data
+    ) external view returns (bytes memory);
+}
+
+interface IArbitrumBCTransferGateway is IArbitrumTransferGateway {
+    event DepositInitiated(
+        address l1Token,
+        address indexed _from,
+        address indexed _to,
+        uint256 indexed _sequenceNumber,
+        uint256 _amount
+    );
+
+    event WithdrawalFinalized(
+        address l1Token,
+        address indexed _from,
+        address indexed _to,
+        uint256 indexed _exitNum,
+        uint256 _amount
+    );
+}
+
+interface IArbitrumSCTransferGateway is IArbitrumTransferGateway {
+    event DepositFinalized(
+        address indexed l1Token,
+        address indexed _from,
+        address indexed _to,
+        uint256 _amount
+    );
+
+    event WithdrawalInitiated(
+        address l1Token,
+        address indexed _from,
+        address indexed _to,
+        uint256 indexed _l2ToL1Id,
+        uint256 _exitNum,
+        uint256 _amount
+    );
+}

contracts/_interfaces/bridge-gateways/IChainBridgeGateway.sol

@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+import {IBCRebaseGatewayEvents, ISCRebaseGatewayEvents, ITransferGatewayEvents} from "./IGateway.sol";
+
+interface IChainBridgeBCRebaseGateway is IBCRebaseGatewayEvents {
+    function validateRebaseReport(uint256 globalAmpleforthEpoch, uint256 globalAMPLSupply) external;
+}
+
+interface IChainBridgeSCRebaseGateway is ISCRebaseGatewayEvents {
+    function reportRebase(uint256 globalAmpleforthEpoch, uint256 globalAMPLSupply) external;
+}
+
+interface IChainBridgeBCTransferGateway is ITransferGatewayEvents {
+    function validateAndLock(
+        address sender,
+        address recipientInTargetChain,
+        uint256 amount,
+        uint256 globalAMPLSupply
+    ) external;
+
+    function unlock(
+        address senderInSourceChain,
+        address recipient,
+        uint256 amount,
+        uint256 globalAMPLSupply
+    ) external;
+}
+
+interface IChainBridgeSCTransferGateway is ITransferGatewayEvents {
+    function mint(
+        address senderInSourceChain,
+        address recipient,
+        uint256 amount,
+        uint256 globalAMPLSupply
+    ) external;
+
+    function validateAndBurn(
+        address sender,
+        address recipientInTargetChain,
+        uint256 amount,
+        uint256 globalAMPLSupply
+    ) external;
+}

contracts/_interfaces/bridge-gateways/ITransferGatewayEvents.sol → contracts/_interfaces/bridge-gateways/IGateway.sol

@@ -1,5 +1,29 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
+interface IBCRebaseGatewayEvents {
+    // Logged on the base chain gateway (ethereum) when rebase report is propagated out
+    event XCRebaseReportOut(
+        // epoch from the Ampleforth Monetary Policy on the base chain
+        uint256 globalAmpleforthEpoch,
+        // totalSupply of AMPL ERC-20 contract on the base chain
+        uint256 globalAMPLSupply
+    );
+}
+
+interface ISCRebaseGatewayEvents {
+    // Logged on the satellite chain gateway when bridge reports most recent rebase
+    event XCRebaseReportIn(
+        // new value coming in from the base chain
+        uint256 globalAmpleforthEpoch,
+        // new value coming in from the base chain
+        uint256 globalAMPLSupply,
+        // existing value on the satellite chain
+        uint256 recordedGlobalAmpleforthEpoch,
+        // existing value on the satellite chain
+        uint256 recordedGlobalAMPLSupply
+    );
+}
+
 interface ITransferGatewayEvents {
     // Logged on source chain when cross-chain transfer is initiated
     event XCTransferOut(

contracts/_interfaces/bridge-gateways/IMaticGateway.sol

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+import {IBCRebaseGatewayEvents, ISCRebaseGatewayEvents, ITransferGatewayEvents} from "./IGateway.sol";
+
+interface IMaticBCRebaseGateway is IBCRebaseGatewayEvents {
+    function reportRebase() external;
+}
+
+interface IMaticSCRebaseGateway is ISCRebaseGatewayEvents {}
+
+interface IMaticTransferGateway is ITransferGatewayEvents {
+    function transfer(address recipientInTargetChain, uint256 amount) external;
+}

contracts/_mocks/MockArbitrum.sol

@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+pragma solidity 0.6.11;
+pragma experimental ABIEncoderV2;
+
+import {InboxMock} from "arb-bridge-peripherals/contracts/tokenbridge/test/InboxMock.sol";
+import {L1ArbitrumMessenger} from "arb-bridge-peripherals/contracts/tokenbridge/ethereum/L1ArbitrumMessenger.sol";
+import {L2ArbitrumMessenger} from "arb-bridge-peripherals/contracts/tokenbridge/arbitrum/L2ArbitrumMessenger.sol";
+import {L1ArbitrumTestMessenger} from "arb-bridge-peripherals/contracts/tokenbridge/test/GatewayTest.sol";
+import {L2ArbitrumTestMessenger} from "arb-bridge-peripherals/contracts/tokenbridge/test/GatewayTest.sol";
+import {IBridge} from "arb-bridge-peripherals/contracts/tokenbridge/test/GatewayTest.sol";
+import {AMPLArbitrumGateway} from "../base-chain/bridge-gateways/AMPLArbitrumGateway.sol";
+import {ArbitrumXCAmpleGateway} from "../satellite-chain/bridge-gateways/ArbitrumXCAmpleGateway.sol";
+
+contract MockArbitrumInbox is InboxMock {}
+
+// Mocking sendTxToL2
+// https://shorturl.at/dgABO
+contract MockAMPLArbitrumGateway is L1ArbitrumTestMessenger, AMPLArbitrumGateway {
+    constructor(
+        address ampl_,
+        address policy_,
+        address vault_
+    ) public AMPLArbitrumGateway(ampl_, policy_, vault_) {}
+
+    function sendTxToL2(
+        address _inbox,
+        address _to,
+        address _user,
+        uint256 _l1CallValue,
+        uint256 _l2CallValue,
+        uint256 _maxSubmissionCost,
+        uint256 _maxGas,
+        uint256 _gasPriceBid,
+        bytes memory _data
+    ) internal virtual override(L1ArbitrumMessenger, L1ArbitrumTestMessenger) returns (uint256) {
+        return
+            L1ArbitrumTestMessenger.sendTxToL2(
+                _inbox,
+                _to,
+                _user,
+                _l1CallValue,
+                _l2CallValue,
+                _maxSubmissionCost,
+                _maxGas,
+                _gasPriceBid,
+                _data
+            );
+    }
+
+    function getL2ToL1Sender(address _inbox)
+        internal
+        view
+        virtual
+        override(L1ArbitrumMessenger, L1ArbitrumTestMessenger)
+        returns (address)
+    {
+        return L1ArbitrumTestMessenger.getL2ToL1Sender(_inbox);
+    }
+
+    function getBridge(address _inbox)
+        internal
+        view
+        virtual
+        override(L1ArbitrumMessenger, L1ArbitrumTestMessenger)
+        returns (IBridge)
+    {
+        return L1ArbitrumTestMessenger.getBridge(_inbox);
+    }
+}
+
+contract MockArbitrumXCAmpleGateway is L2ArbitrumTestMessenger, ArbitrumXCAmpleGateway {
+    constructor(address xcAmple_, address xcController_)
+        public
+        ArbitrumXCAmpleGateway(xcAmple_, xcController_)
+    {}
+
+    function sendTxToL1(
+        uint256 _l1CallValue,
+        address _from,
+        address _to,
+        bytes memory _data
+    ) internal virtual override(L2ArbitrumMessenger, L2ArbitrumTestMessenger) returns (uint256) {
+        return L2ArbitrumTestMessenger.sendTxToL1(_l1CallValue, _from, _to, _data);
+    }
+}