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Improve solidity code for PNA (#1275)
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* Improve PNA implementation

* More improvents to ERC20 token

* Fix implementation of Assets._sendForeignToken

* Fix build payload for foreign token

---------

Co-authored-by: ron <yrong1997@gmail.com>
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@vgeddes @yrong
vgeddes and yrong committed Aug 28, 2024
1 parent f892da4 commit 84bb52c
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Showing 14 changed files with 341 additions and 378 deletions.
27 changes: 3 additions & 24 deletions contracts/src/AgentExecutor.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,6 @@ import {SubstrateTypes} from "./SubstrateTypes.sol";

import {IERC20} from "./interfaces/IERC20.sol";
import {SafeTokenTransfer, SafeNativeTransfer} from "./utils/SafeTransfer.sol";
import {ERC20} from "./ERC20.sol";
import {Gateway} from "./Gateway.sol";

/// @title Code which will run within an `Agent` using `delegatecall`.
Expand All @@ -16,40 +15,20 @@ contract AgentExecutor {
using SafeTokenTransfer for IERC20;
using SafeNativeTransfer for address payable;

/// @dev Execute a message which originated from the Polkadot side of the bridge. In other terms,
/// the `data` parameter is constructed by the BridgeHub parachain.
///
function execute(bytes memory data) external {
(AgentExecuteCommand command, bytes memory params) = abi.decode(data, (AgentExecuteCommand, bytes));
if (command == AgentExecuteCommand.TransferToken) {
(address token, address recipient, uint128 amount) = abi.decode(params, (address, address, uint128));
_transferToken(token, recipient, amount);
}
}

/// @dev Transfer ether to `recipient`. Unlike `_transferToken` This logic is not nested within `execute`,
/// as the gateway needs to control an agent's ether balance directly.
///
function transferNative(address payable recipient, uint256 amount) external {
recipient.safeNativeTransfer(amount);
}

/// @dev Transfer ERC20 to `recipient`. Only callable via `execute`.
function _transferToken(address token, address recipient, uint128 amount) internal {
IERC20(token).safeTransfer(recipient, amount);
}

/// @dev Transfer ERC20 to `recipient`. Only callable via `execute`.
function transferToken(address token, address recipient, uint128 amount) external {
_transferToken(token, recipient, amount);
}

/// @dev Mint ERC20 token to `recipient`.
function mintToken(address token, address recipient, uint256 amount) external {
ERC20(token).mint(recipient, amount);
}

function burnToken(address token, address sender, uint256 amount) external {
ERC20(token).burn(sender, amount);
/// @dev Transfer ERC20 to `recipient`. Only callable via `execute`.
function _transferToken(address token, address recipient, uint128 amount) internal {
IERC20(token).safeTransfer(recipient, amount);
}
}
232 changes: 153 additions & 79 deletions contracts/src/Assets.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@ import {Address} from "./utils/Address.sol";
import {AgentExecutor} from "./AgentExecutor.sol";
import {Agent} from "./Agent.sol";
import {Call} from "./utils/Call.sol";
import {ERC20} from "./ERC20.sol";
import {Token} from "./Token.sol";

/// @title Library for implementing Ethereum->Polkadot ERC20 transfers.
library Assets {
Expand Down Expand Up @@ -108,6 +108,41 @@ library Assets {
) external returns (Ticket memory ticket) {
AssetsStorage.Layout storage $ = AssetsStorage.layout();

TokenInfo storage info = $.tokenRegistry[token];

if (!info.isRegistered) {
revert TokenNotRegistered();
}

if (info.foreignID == bytes32(0)) {
return _sendNativeToken(
token, sender, destinationChain, destinationAddress, destinationChainFee, maxDestinationChainFee, amount
);
} else {
return _sendForeignToken(
info.foreignID,
token,
sender,
destinationChain,
destinationAddress,
destinationChainFee,
maxDestinationChainFee,
amount
);
}
}

function _sendNativeToken(
address token,
address sender,
ParaID destinationChain,
MultiAddress calldata destinationAddress,
uint128 destinationChainFee,
uint128 maxDestinationChainFee,
uint128 amount
) internal returns (Ticket memory ticket) {
AssetsStorage.Layout storage $ = AssetsStorage.layout();

// Lock the funds into AssetHub's agent contract
_transferToAgent($.assetHubAgent, token, sender, amount);

Expand Down Expand Up @@ -159,6 +194,98 @@ library Assets {
emit IGateway.TokenSent(token, sender, destinationChain, destinationAddress, amount);
}

function _sendForeignTokenCosts(
ParaID destinationChain,
uint128 destinationChainFee,
uint128 maxDestinationChainFee
) internal view returns (Costs memory costs) {
AssetsStorage.Layout storage $ = AssetsStorage.layout();
if ($.assetHubParaID == destinationChain) {
costs.foreign = $.assetHubReserveTransferFee;
} else {
// Reduce the ability for users to perform arbitrage by exploiting a
// favourable exchange rate. For example supplying Ether
// and gaining a more valuable amount of DOT on the destination chain.
//
// Also prevents users from mistakenly sending more fees than would be required
// which has negative effects like draining AssetHub's sovereign account.
//
// For safety, `maxDestinationChainFee` should be less valuable
// than the gas cost to send tokens.
if (destinationChainFee > maxDestinationChainFee) {
revert InvalidDestinationFee();
}

// If the final destination chain is not AssetHub, then the fee needs to additionally
// include the cost of executing an XCM on the final destination parachain.
costs.foreign = $.assetHubReserveTransferFee + destinationChainFee;
}
// We don't charge any extra fees beyond delivery costs
costs.native = 0;
}

// @dev Transfer Polkadot-native tokens back to Polkadot
function _sendForeignToken(
bytes32 foreignID,
address token,
address sender,
ParaID destinationChain,
MultiAddress calldata destinationAddress,
uint128 destinationChainFee,
uint128 maxDestinationChainFee,
uint128 amount
) internal returns (Ticket memory ticket) {
AssetsStorage.Layout storage $ = AssetsStorage.layout();

Token(token).burn(sender, amount);

ticket.dest = $.assetHubParaID;
ticket.costs = _sendForeignTokenCosts(destinationChain, destinationChainFee, maxDestinationChainFee);

// Construct a message payload
if (destinationChain == $.assetHubParaID) {
// The funds will be minted into the receiver's account on AssetHub
if (destinationAddress.isAddress32()) {
// The receiver has a 32-byte account ID
ticket.payload = SubstrateTypes.SendForeignTokenToAssetHubAddress32(
foreignID, destinationAddress.asAddress32(), $.assetHubReserveTransferFee, amount
);
} else {
// AssetHub does not support 20-byte account IDs
revert Unsupported();
}
} else {
if (destinationChainFee == 0) {
revert InvalidDestinationFee();
}
if (destinationAddress.isAddress32()) {
// The receiver has a 32-byte account ID
ticket.payload = SubstrateTypes.SendForeignTokenToAddress32(
foreignID,
destinationChain,
destinationAddress.asAddress32(),
$.assetHubReserveTransferFee,
destinationChainFee,
amount
);
} else if (destinationAddress.isAddress20()) {
// The receiver has a 20-byte account ID
ticket.payload = SubstrateTypes.SendForeignTokenToAddress20(
foreignID,
destinationChain,
destinationAddress.asAddress20(),
$.assetHubReserveTransferFee,
destinationChainFee,
amount
);
} else {
revert Unsupported();
}
}

emit IGateway.TokenSent(token, sender, destinationChain, destinationAddress, amount);
}

function registerTokenCosts() external view returns (Costs memory costs) {
return _registerTokenCosts();
}
Expand Down Expand Up @@ -195,90 +322,31 @@ library Assets {
emit IGateway.TokenRegistrationSent(token);
}

// @dev Transfer polkadot native tokens back
function sendForeignToken(
address agent,
address executor,
TokenInfo storage info,
address sender,
ParaID destinationChain,
MultiAddress calldata destinationAddress,
uint128 destinationChainFee,
uint128 amount
) external returns (Ticket memory ticket) {
if (destinationChainFee == 0) {
revert InvalidDestinationFee();
}
// Polkadot-native token: burn wrapped token
_burnToken(executor, agent, info.token, sender, amount);

ticket.dest = destinationChain;
ticket.costs = _sendForeignTokenCosts(destinationChainFee);

if (destinationAddress.isAddress32()) {
// The receiver has a 32-byte account ID
ticket.payload = SubstrateTypes.SendForeignTokenToAddress32(
info.tokenID, destinationChain, destinationAddress.asAddress32(), destinationChainFee, amount
);
} else if (destinationAddress.isAddress20()) {
// The receiver has a 20-byte account ID
ticket.payload = SubstrateTypes.SendForeignTokenToAddress20(
info.tokenID, destinationChain, destinationAddress.asAddress20(), destinationChainFee, amount
);
} else {
revert Unsupported();
}

emit IGateway.TokenSent(info.token, sender, destinationChain, destinationAddress, amount);
}

function _burnToken(address agentExecutor, address agent, address token, address sender, uint256 amount) internal {
bytes memory call = abi.encodeCall(AgentExecutor.burnToken, (token, sender, amount));
(bool success, bytes memory returndata) = (Agent(payable(agent)).invoke(agentExecutor, call));
Call.verifyResult(success, returndata);
}

function _sendForeignTokenCosts(uint128 destinationChainFee) internal pure returns (Costs memory costs) {
costs.foreign = destinationChainFee;
costs.native = 0;
}

// @dev Register a new fungible Polkadot token for an agent
function registerForeignToken(
bytes32 agentID,
address agent,
bytes32 tokenID,
string memory name,
string memory symbol,
uint8 decimals
) external {
function registerForeignToken(bytes32 foreignTokenID, string memory name, string memory symbol, uint8 decimals)
external
{
AssetsStorage.Layout storage $ = AssetsStorage.layout();
if ($.tokenRegistryByID[tokenID].isRegistered == true) {
if ($.tokenAddressOf[foreignTokenID] != address(0)) {
revert TokenAlreadyRegistered();
}
ERC20 foreignToken = new ERC20(agent, name, symbol, decimals);
address token = address(foreignToken);
TokenInfo memory info =
TokenInfo({isRegistered: true, isForeign: true, tokenID: tokenID, agentID: agentID, token: token});
$.tokenRegistry[token] = info;
$.tokenRegistryByID[tokenID] = info;
emit IGateway.ForeignTokenRegistered(tokenID, agentID, token);
Token token = new Token(name, symbol, decimals);
TokenInfo memory info = TokenInfo({isRegistered: true, foreignID: foreignTokenID});

$.tokenAddressOf[foreignTokenID] = address(token);
$.tokenRegistry[address(token)] = info;

emit IGateway.ForeignTokenRegistered(foreignTokenID, address(token));
}

// @dev Mint foreign token from Polkadot
function mintForeignToken(address executor, address agent, bytes32 tokenID, address recipient, uint256 amount)
external
{
address token = _tokenAddressOf(tokenID);
bytes memory call = abi.encodeCall(AgentExecutor.mintToken, (token, recipient, amount));
(bool success,) = Agent(payable(agent)).invoke(executor, call);
if (!success) {
revert TokenMintFailed();
}
function mintForeignToken(bytes32 foreignTokenID, address recipient, uint256 amount) external {
address token = _ensureTokenAddressOf(foreignTokenID);
Token(token).mint(recipient, amount);
}

// @dev Transfer ERC20 to `recipient`
function transferToken(address executor, address agent, address token, address recipient, uint128 amount)
function transferNativeToken(address executor, address agent, address token, address recipient, uint128 amount)
external
{
bytes memory call = abi.encodeCall(AgentExecutor.transferToken, (token, recipient, amount));
Expand All @@ -290,15 +358,21 @@ library Assets {

// @dev Get token address by tokenID
function tokenAddressOf(bytes32 tokenID) external view returns (address) {
return _tokenAddressOf(tokenID);
AssetsStorage.Layout storage $ = AssetsStorage.layout();
return $.tokenAddressOf[tokenID];
}

// @dev Get token address by tokenID
function _tokenAddressOf(bytes32 tokenID) internal view returns (address) {
function _ensureTokenAddressOf(bytes32 tokenID) internal view returns (address) {
AssetsStorage.Layout storage $ = AssetsStorage.layout();
if ($.tokenRegistryByID[tokenID].isRegistered == false) {
if ($.tokenAddressOf[tokenID] == address(0)) {
revert TokenNotRegistered();
}
return $.tokenRegistryByID[tokenID].token;
return $.tokenAddressOf[tokenID];
}

function _isTokenRegistered(address token) internal view returns (bool) {
AssetsStorage.Layout storage $ = AssetsStorage.layout();
return $.tokenRegistry[token].isRegistered;
}
}
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