refactor: separation of the app-agnostic gateway interfaces and the K…

…leros-specific gateways

contracts/src/bridge/FastBridgeSender.sol

@@ -57,7 +57,7 @@ contract FastBridgeSender is IFastBridgeSender, ISafeBridgeSender {
     /**
      * @dev Constructor.
      * @param _epochPeriod The duration between epochs.
-     * @param _safeBridgeReceiver The the Safe Bridge Router on Ethereum to the foreign chain.
+     * @param _safeBridgeReceiver The the Safe Bridge Router on Ethereum to the receiving chain.
      */
     constructor(uint256 _epochPeriod, address _safeBridgeReceiver) {
         epochPeriod = _epochPeriod;
@@ -103,8 +103,7 @@ contract FastBridgeSender is IFastBridgeSender, ISafeBridgeSender {
     }
 
     /**
-     * Sends a batch of arbitrary message from one domain to another
-     * via the fast bridge mechanism.
+     * Sends a batch of arbitrary message from one domain to another via the fast bridge mechanism.
      */
     function sendBatch() external override {
         uint256 epoch = block.timestamp / epochPeriod;

contracts/src/bridge/interfaces/IReceiverGateway.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: MIT
+
+/**
+ *  @authors: [@jaybuidl, @shotaronowhere]
+ *  @reviewers: []
+ *  @auditors: []
+ *  @bounties: []
+ *  @deployments: []
+ */
+
+pragma solidity ^0.8.0;
+
+import "../../bridge/interfaces/IFastBridgeReceiver.sol";
+
+interface IReceiverGateway {
+    function fastBridgeReceiver() external view returns (IFastBridgeReceiver);
+
+    function senderChainID() external view returns (uint256);
+
+    function senderGateway() external view returns (address);
+}

contracts/src/bridge/interfaces/ISafeBridgeSender.sol

@@ -14,8 +14,8 @@ abstract contract ISafeBridgeSender {
     /**
      * Sends an arbitrary message from one domain to another.
      *
-     * @param _receiver The foreign chain contract address who will receive the calldata
-     * @param _calldata The home chain encoded message data.
+     * @param _receiver The contract address which will receive the calldata on the receiving chain.
+     * @param _calldata The encoded message data to send.
      * @return Unique id to track the message request/transaction.
      */
     function _sendSafe(address _receiver, bytes memory _calldata) internal virtual returns (bytes32);

contracts/src/bridge/interfaces/ISenderGateway.sol

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: MIT
+
+/**
+ *  @authors: [@jaybuidl, @shotaronowhere]
+ *  @reviewers: []
+ *  @auditors: []
+ *  @bounties: []
+ *  @deployments: []
+ */
+
+pragma solidity ^0.8.0;
+
+import "../../bridge/interfaces/IFastBridgeSender.sol";
+
+interface ISenderGateway {
+    function fastBridgeSender() external view returns (IFastBridgeSender);
+
+    function receiverChainID() external view returns (uint256);
+
+    function receiverGateway() external view returns (address);
+}

contracts/src/bridge/single-message/FastBridgeSenderToEthereum.sol

@@ -35,7 +35,7 @@ contract FastBridgeSenderToEthereum is SafeBridgeSenderToEthereum, IFastBridgeSe
 
     address public governor; // The governor of the contract.
     IFastBridgeReceiver public fastBridgeReceiver; // The address of the Fast Bridge on Ethereum.
-    address public fastBridgeSender; // The address of the Fast Bridge sender on Arbitrum, generally the Home Gateway.
+    address public fastBridgeSender; // The address of the Fast Bridge sender on Arbitrum, generally the Sender Gateway.
     uint256 public currentTicketID = 1; // Zero means not set, start at 1.
     mapping(uint256 => Ticket) public tickets; // The tickets by ticketID.
 
@@ -52,7 +52,7 @@ contract FastBridgeSenderToEthereum is SafeBridgeSenderToEthereum, IFastBridgeSe
      * @dev Constructor.
      * @param _governor The governor's address.
      * @param _fastBridgeReceiver The address of the Fast Bridge on Ethereum.
-     * @param _fastBridgeSender The address of the Fast Bridge sender on Arbitrum, generally the Home Gateway.
+     * @param _fastBridgeSender The address of the Fast Bridge sender on Arbitrum, generally the Sender Gateway.
      */
     constructor(
         address _governor,

contracts/src/bridge/test/FastBridgeSenderMock.sol

@@ -63,7 +63,7 @@ contract FastBridgeSenderMock is IFastBridgeSender, ISafeBridgeSender {
     /**
      * @dev Constructor.
      * @param _epochPeriod The duration between epochs.
-     * @param _safeBridgeReceiver The the Safe Bridge Router on Ethereum to the foreign chain.
+     * @param _safeBridgeReceiver The the Safe Bridge Router on Ethereum to the receiving chain.
      * @param _arbsys The address of the mock ArbSys contract.
      */
     constructor(

contracts/src/gateway/interfaces/IForeignGatewayMock.sol → contracts/src/bridge/test/gateways/IReceiverGatewayMock.sol

@@ -10,9 +10,9 @@
 
 pragma solidity ^0.8.0;
 
-import "./IForeignGatewayBase.sol";
+import "../../interfaces/IReceiverGateway.sol";
 
-interface IForeignGatewayMock is IForeignGatewayBase {
+interface IReceiverGatewayMock is IReceiverGateway {
     /**
      * Receive the message from the home gateway.
      */

contracts/src/bridge/test/gateways/ISenderGatewayMock.sol

@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../../interfaces/ISenderGateway.sol";
+
+interface ISenderGatewayMock is ISenderGateway {}

contracts/src/bridge/test/gateways/ReceiverGatewayMock.sol

@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: MIT
+
+/**
+ *  @authors: [@shotaronowhere]
+ *  @reviewers: []
+ *  @auditors: []
+ *  @bounties: []
+ *  @deployments: []
+ */
+
+pragma solidity ^0.8.0;
+
+import "./IReceiverGatewayMock.sol";
+
+/**
+ * Receiver Gateway Mock
+ * Counterpart of `SenderGatewayMock`
+ */
+contract ReceiverGatewayMock is IReceiverGateway {
+    IFastBridgeReceiver public immutable fastBridgeReceiver;
+    address public immutable override senderGateway;
+    uint256 public immutable override senderChainID;
+
+    uint256 public messageCount;
+    uint256 public data;
+
+    constructor(
+        IFastBridgeReceiver _fastBridgeReceiver,
+        address _senderGateway,
+        uint256 _senderChainID
+    ) {
+        fastBridgeReceiver = _fastBridgeReceiver;
+        senderGateway = _senderGateway;
+        senderChainID = _senderChainID;
+    }
+
+    modifier onlyFromFastBridge() {
+        require(address(fastBridgeReceiver) == msg.sender, "Fast Bridge only.");
+        _;
+    }
+
+    /**
+     * Receive the message from the sender gateway.
+     */
+    function receiveMessage(address _messageSender) external onlyFromFastBridge {
+        require(_messageSender == senderGateway, "Only the sender gateway is allowed.");
+        _receiveMessage();
+    }
+
+    /**
+     * Receive the message from the sender gateway.
+     */
+    function receiveMessage(address _messageSender, uint256 _data) external onlyFromFastBridge {
+        require(_messageSender == senderGateway, "Only the sender gateway is allowed.");
+        _receiveMessage(_data);
+    }
+
+    function _receiveMessage() internal {
+        messageCount++;
+    }
+
+    function _receiveMessage(uint256 _data) internal {
+        messageCount++;
+        data = _data;
+    }
+}

contracts/src/bridge/test/gateways/SenderGatewayMock.sol

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: MIT
+
+/**
+ *  @authors: [@shotaronowhere]
+ *  @reviewers: []
+ *  @auditors: []
+ *  @bounties: []
+ *  @deployments: []
+ */
+
+pragma solidity ^0.8.0;
+
+import "./IReceiverGatewayMock.sol";
+import "../../interfaces/ISenderGateway.sol";
+
+/**
+ * Sender Gateway
+ * Counterpart of `ReceiverGatewayMock`
+ */
+contract SenderGatewayMock is ISenderGateway {
+    IFastBridgeSender public immutable fastBridgeSender;
+    address public override receiverGateway;
+    uint256 public immutable override receiverChainID;
+
+    struct RelayedData {
+        uint256 arbitrationCost;
+        address relayer;
+    }
+    mapping(bytes32 => RelayedData) public disputeHashtoRelayedData;
+
+    constructor(
+        IFastBridgeSender _fastBridgeSender,
+        address _receiverGateway,
+        uint256 _receiverChainID
+    ) {
+        fastBridgeSender = _fastBridgeSender;
+        receiverGateway = _receiverGateway;
+        receiverChainID = _receiverChainID;
+    }
+
+    function sendFastMessage(uint256 _data) external {
+        bytes4 methodSelector = IReceiverGatewayMock.receiveMessage.selector;
+        bytes memory data = abi.encodeWithSelector(methodSelector, _data);
+
+        fastBridgeSender.sendFast(receiverGateway, data);
+    }
+}