feat(ethereum contracts): ERC20Gateway ethereum contract

ethereum/client/build.rs

@@ -1,8 +1,7 @@
 use std::process::Command;
 
 fn main() {
-    println!("cargo::rerun-if-changed=../src");
-    println!("cargo::rerun-if-changed=../lib");
+    println!("cargo::rerun-if-changed=*");
 
     Command::new("forge")
         .arg("build")

ethereum/src/ERC20Gateway.sol

@@ -0,0 +1,74 @@
+pragma solidity ^0.8.24;
+
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import {Context} from "@openzeppelin/contracts/utils/Context.sol";
+
+import {Address} from "@openzeppelin/contracts/utils/Address.sol";
+
+import {IERC20Gateway} from "./interfaces/IERC20Gateway.sol";
+import {VFT_TREASURY_ADDRESS} from "./libraries/Environment.sol";
+import {IMessageQueue, IMessageQueueReceiver, VaraMessage} from "./interfaces/IMessageQueue.sol";
+import {ERC20VaraSupply} from "./ERC20VaraSupply.sol";
+
+contract ERC20Gateway is IERC20Gateway, Context, IMessageQueueReceiver {
+    address immutable MESSAGE_QUEUE_ADDRESS;
+
+    constructor(address message_queue) {
+        MESSAGE_QUEUE_ADDRESS = message_queue;
+    }
+
+    /** @dev Request token bridging. When the bridging is requested tokens are burned
+     * from account that've sent transaction and `BridgingRequested` event is emitted that later can be verified
+     * on other side of bridge. Allowance needs to allow gateway contract transferring `amount` of tokens.
+     *
+     * @param token token address to transfer over bridge
+     * @param amount quantity of tokens to transfer over bridge
+     * @param to destination of transfer on VARA network
+     */
+    function requestBridging(address token, uint256 amount, bytes32 to) public {
+        ERC20VaraSupply(token).burnFrom(_msgSender(), amount);
+        emit BridgingRequested(_msgSender(), to, token, amount);
+    }
+
+    /** @dev Accept bridging request made on other side of bridge.
+     * This request can be sent by `MessageQueue` only. When such a request is accpeted, tokens
+     * are minted to the corresponding account address, specified in `vara_msg`.
+     *
+     * Expected `payload` in `VaraMessage` consisits of these:
+     *  - `receiver` - account to mint tokens to
+     *  - `token` - token to mint
+     *  - `amount` - amount of tokens to mint
+     *
+     * @param vara_msg `VaraMessage` received from MessageQueue.
+     */
+    function processVaraMessage(
+        VaraMessage calldata vara_msg
+    ) external returns (bool) {
+        uint160 receiver;
+        uint160 token;
+        uint256 amount;
+        if (msg.sender != MESSAGE_QUEUE_ADDRESS) {
+            revert NotAuthorized();
+        }
+        if (vara_msg.data.length != 20 + 20 + 32) {
+            revert BadArguments();
+        }
+        if (vara_msg.receiver != address(this)) {
+            revert BadEthAddress();
+        }
+        if (vara_msg.sender != VFT_TREASURY_ADDRESS) {
+            revert BadVaraAddress();
+        }
+
+        assembly {
+            receiver := shr(96, calldataload(0xC4))
+            token := shr(96, calldataload(0xD8))
+            amount := calldataload(0xEC)
+        }
+
+        ERC20VaraSupply(address(token)).mint(address(receiver), amount);
+
+        emit BridgingAccepted(address(receiver), address(token), amount);
+        return true;
+    }
+}

ethereum/src/ERC20Treasury.sol

@@ -6,8 +6,8 @@ import {Context} from "@openzeppelin/contracts/utils/Context.sol";
 import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
 import {Address} from "@openzeppelin/contracts/utils/Address.sol";
 
-import {IERC20Treasury, WithdrawMessage} from "./interfaces/IERC20Treasury.sol";
-import {GRC_20_GATEWAY_ADDRESS} from "./libraries/Environment.sol";
+import {IERC20Treasury} from "./interfaces/IERC20Treasury.sol";
+import {VFT_GATEWAY_ADDRESS} from "./libraries/Environment.sol";
 import {IMessageQueue, IMessageQueueReceiver, VaraMessage} from "./interfaces/IMessageQueue.sol";
 
 contract ERC20Treasury is IERC20Treasury, Context, IMessageQueueReceiver {
@@ -55,7 +55,7 @@ contract ERC20Treasury is IERC20Treasury, Context, IMessageQueueReceiver {
         if (vara_msg.receiver != address(this)) {
             revert BadEthAddress();
         }
-        if (vara_msg.sender != GRC_20_GATEWAY_ADDRESS) {
+        if (vara_msg.sender != VFT_GATEWAY_ADDRESS) {
             revert BadVaraAddress();
         }
 

ethereum/src/ERC20VaraSupply.sol

@@ -0,0 +1,17 @@
+pragma solidity ^0.8.24;
+
+import {ERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import {ERC20Burnable} from "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";
+import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
+
+contract ERC20VaraSupply is ERC20Burnable, Ownable {
+    constructor(
+        address owner,
+        string memory _name,
+        string memory _symbol
+    ) ERC20(_name, _symbol) Ownable(owner) {}
+
+    function mint(address to, uint256 amount) public onlyOwner {
+        _mint(to, amount);
+    }
+}

ethereum/src/interfaces/IERC20Gateway.sol

@@ -0,0 +1,35 @@
+pragma solidity ^0.8.24;
+
+struct BridgingRequest {
+    address receiver;
+    address token;
+    uint128 amount;
+}
+
+interface IERC20Gateway {
+    error NotAuthorized();
+    error BadArguments();
+    error BadEthAddress();
+    error BadVaraAddress();
+
+    event BridgingRequested(
+        address indexed from,
+        bytes32 indexed to,
+        address indexed token,
+        uint256 amount
+    );
+    event BridgingAccepted(
+        address indexed to,
+        address indexed token,
+        uint256 amount
+    );
+}
+
+library Packer {
+    function pack(
+        BridgingRequest calldata message
+    ) external pure returns (bytes memory) {
+        return
+            abi.encodePacked(message.receiver, message.token, message.amount);
+    }
+}

ethereum/src/libraries/Environment.sol

@@ -1,7 +1,11 @@
 pragma solidity ^0.8.24;
 
+// ALICE
+bytes32 constant VFT_GATEWAY_ADDRESS = bytes32(
+    0xd43593c715fdd31c61141abd04a99fd6822c8558854ccde39a5684e7a56da27d
+);
 
 // ALICE
-bytes32 constant GRC_20_GATEWAY_ADDRESS = bytes32(
+bytes32 constant VFT_TREASURY_ADDRESS = bytes32(
     0xd43593c715fdd31c61141abd04a99fd6822c8558854ccde39a5684e7a56da27d
 );