Feat: Add ERC-7802 Facet for Cross-Chain Token Interoperability

src/ERC7802/ERC7802Facet.sol

@@ -0,0 +1,148 @@
+    // SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+contract ERC7802Facet {
+    /// @notice Revert when a provided receiver is invalid(e.g,zero address) .
+    /// @param _receiver The invalid reciever address.
+    error ERC7802InvalidReciever(address _receiver);
+
+    /// @notice Thrown when the sender address is invalid (e.g., zero address).
+    /// @param _sender The invalid sender address.
+
+    error ERC7802InvalidSender(address _sender);
+
+    /// @notice Revert when caller is not a trusted bridge.
+    /// @param _caller The unauthorized caller.
+    error ERC7802InvalidBridgeAccount(address _caller);
+
+    // @notice Revert when caller address is invalid.
+    /// @param _caller is the invalid address.
+    error ERC7802InvalidCallerAddress(address _caller);
+
+    error ERC7802InvalidOwner(address bridge);
+
+    // @notice Revert when an interface id is not supported. // the interfaces supported are IERC165 and 7805
+    /// @param interfaceId The unsupported interface id.
+    error ERC7802InvalidInterfaceId(bytes4 interfaceId);
+
+    error ERC7802InsufficientBalance(address from, uint256 accountBalance, uint256 value);
+    /// @notice Emitted when tokens are minted via a cross-chain bridge.
+    /// @param to The recipient of minted tokens.
+    /// @param amount The amount minted.
+    /// @param sender The bridge account that triggered the mint (msg.sender).
+
+    event CrosschainMint(address indexed to, uint256 amount, address indexed sender);
+
+    /// @notice Emitted when a crosschain transfer burns tokens.
+    /// @param from     Address of the account tokens are being burned from.
+    /// @param amount   Amount of tokens burned.
+    /// @param sender   Address of the caller (msg.sender) who invoked crosschainBurn.
+    event CrosschainBurn(address indexed from, uint256 amount, address indexed sender);
+
+    /// @notice Mint tokens through a crosschain transfer.
+    /// @param to     Address to mint tokens to.
+    /// @param amount Amount of tokens to mint.
+
+    event Transfer(address indexed from, address indexed to, uint256 amount);
+
+    /// @notice Emitted when an interface ID is registered or supported.
+    /// @param interfaceId The supported interface identifier.
+    event Interface(bytes4 indexed interfaceId);
+
+    /// @notice Storage slot for ERC-7802 using ERC8042
+
+    bytes32 constant STORAGE_POSITION = keccak256("compose.erc7802");
+
+    struct ERC7802Storage {
+        address owner;
+        uint256 totalSupply;
+        mapping(address owner => uint256 balance) balanceOf;
+        mapping(address => bool) _trustedBridges;
+        mapping(bytes4 => bool) _supportedInterfaces;
+    }
+
+    /// @notice Return storage pointer to ERC7802Storage
+    /// @dev Inline assembly to point storage to a fixed slot.
+    /// @return s Pointer to storage struct.
+
+    function getStorage() internal pure returns (ERC7802Storage storage s) {
+        bytes32 position = STORAGE_POSITION;
+
+        assembly {
+            s.slot := position
+        }
+    }
+
+    function getOwner() external view returns (address) {
+        return getStorage().owner;
+    }
+
+    /// @notice Returns the total supply of tokens.
+    /// @return The total token supply.
+
+    function totalSupply() external view returns (uint256) {
+        return getStorage().totalSupply;
+    }
+
+    ///@notice Returns the balance of a specific account.
+    ///@param _account The address of the account.
+    ///@return The account balance.
+
+    function balanceOf(address _account) external view returns (uint256) {
+        return getStorage().balanceOf[_account];
+    }
+
+    /// @notice Internal crosschain mint logic. MUST be called only after validating caller.
+    /// @dev Increases totalSupply and recipient balance and emits CrosschainMint.
+    /// @param _account The account to mint tokens to.
+    /// @param _value The amount to mint.
+    function crooschainMint(address _account, uint256 _value) external {
+        ERC7802Storage storage s = getStorage();
+
+        if (s._trustedBridges[msg.sender] == false) revert ERC7802InvalidBridgeAccount(msg.sender);
+        if (_account == address(0)) revert ERC7802InvalidReciever(address(0));
+
+        unchecked {
+            s.totalSupply += _value;
+            s.balanceOf[_account] += _value;
+        }
+
+        emit CrosschainMint(_account, _value, msg.sender);
+    }
+
+    /// @notice Internal crosschain burn logic. MUST be called only after validating caller.
+    /// @dev Decreases totalSupply and the `from` balance and emits CrosschainBurn.
+    /// @param _from The account to burn tokens from.
+    /// @param _value The amount to burn.
+    function crosschainBurn(address _from, uint256 _value) external {
+        ERC7802Storage storage s = getStorage();
+
+        if (s._trustedBridges[msg.sender] == false) revert ERC7802InvalidBridgeAccount(msg.sender);
+        if (_from == address(0)) revert ERC7802InvalidReciever(address(0));
+
+        uint256 accountBalance = s.balanceOf[_from];
+
+        if (accountBalance < _value) revert ERC7802InsufficientBalance(_from, accountBalance, _value);
+
+        unchecked {
+            s.totalSupply -= _value;
+            s.balanceOf[_from] -= _value;
+        }
+
+        emit CrosschainBurn(_from, _value, msg.sender);
+    }
+
+    //ERC165 and 7805 supports
+    /// @notice Query whether an interface id is supported (ERC-165 style).
+    /// @param interfaceId The interface id to query.
+
+    function supportInterface(bytes4 interfaceId) external {
+        ERC7802Storage storage s = getStorage();
+
+        if (interfaceId != 0x33331994 || interfaceId == 0x01ffc9a7) revert ERC7802InvalidInterfaceId(interfaceId);
+
+        s._supportedInterfaces[interfaceId] = true;
+
+        emit Interface(interfaceId);
+    }
+}

src/ERC7802/libraries/LibERC7802.sol

@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.30;
+
+/// @title LibERC20 — ERC-7802 Library
+/// @notice Provides internal functions and storage layout for ERC-7802 token logic.
+/// @dev Uses ERC-8042 for storage location standardization and ERC-6093 for error conventions
+library LibERC7802 {
+    /// @notice Revert when a provided receiver is invalid(e.g,zero address) .
+    /// @param _receiver The invalid reciever address.
+    error ERC7802InvalidReciever(address _receiver);
+
+    /// @notice Thrown when the sender address is invalid (e.g., zero address).
+    /// @param _sender The invalid sender address.
+
+    error ERC7802InvalidSender(address _sender);
+
+    /// @notice Revert when caller is not a trusted bridge.
+    /// @param _caller The unauthorized caller.
+    error ERC7802InvalidBridgeAccount(address _caller);
+
+    // @notice Revert when caller address is invalid.
+    /// @param _caller is the invalid address.
+    error ERC7802InvalidCallerAddress(address _caller);
+
+    error ERC7802InvalidOwner(address bridge);
+
+    // @notice Revert when an interface id is not supported. // the interfaces supported are IERC165 and 7805
+    /// @param interfaceId The unsupported interface id.
+    error ERC7802InvalidInterfaceId(bytes4 interfaceId);
+
+    error ERC7802InsufficientBalance(address from, uint256 accountBalance, uint256 value);
+    /// @notice Emitted when tokens are minted via a cross-chain bridge.
+    /// @param to The recipient of minted tokens.
+    /// @param amount The amount minted.
+    /// @param sender The bridge account that triggered the mint (msg.sender).
+
+    event CrosschainMint(address indexed to, uint256 amount, address indexed sender);
+
+    /// @notice Emitted when a crosschain transfer burns tokens.
+    /// @param from     Address of the account tokens are being burned from.
+    /// @param amount   Amount of tokens burned.
+    /// @param sender   Address of the caller (msg.sender) who invoked crosschainBurn.
+    event CrosschainBurn(address indexed from, uint256 amount, address indexed sender);
+
+    /// @notice Mint tokens through a crosschain transfer.
+    /// @param to     Address to mint tokens to.
+    /// @param amount Amount of tokens to mint.
+
+    event Transfer(address indexed from, address indexed to, uint256 amount);
+
+    /// @notice Emitted when there is a valid supported interface call
+    ///@param  InterfaceId The supported interface identifier.
+    event Interface(bytes4 indexed InterfaceId);
+
+    /// @notice Storage slot for ERC-7802 using ERC8042 for storage location standardization
+
+    bytes32 constant STORAGE_POSITION = keccak256("compose.erc7802");
+
+    struct ERC7802Storage {
+        address owner;
+        uint256 totalSupply;
+        mapping(address owner => uint256 balance) balanceOf;
+        mapping(address => bool) _trustedBridges;
+        mapping(bytes4 => bool) _supportedInterfaces;
+    }
+
+    /// @notice Return storage pointer to ERC7802Storage
+    /// @dev Inline assembly to point storage to a fixed slot.
+    /// @return s Pointer to storage struct.
+
+    function getStorage() internal pure returns (ERC7802Storage storage s) {
+        bytes32 position = STORAGE_POSITION;
+
+        assembly {
+            s.slot := position
+        }
+    }
+
+    // the bridge account must be a trusted account
+    /// @notice Internal crosschain mint logic. MUST be called only after validating caller.
+    /// @dev Increases totalSupply and recipient balance and emits CrosschainMint.
+    /// @param _account The account to mint tokens to.
+    /// @param _value The amount to mint.
+    function crooschainMint(address _account, uint256 _value) internal {
+        ERC7802Storage storage s = getStorage();
+
+        if (s._trustedBridges[msg.sender] == false) revert ERC7802InvalidBridgeAccount(msg.sender);
+        if (_account == address(0)) revert ERC7802InvalidReciever(address(0));
+
+        unchecked {
+            s.totalSupply += _value;
+            s.balanceOf[_account] += _value;
+        }
+
+        emit CrosschainMint(_account, _value, msg.sender);
+    }
+
+    /// @notice Internal crosschain burn logic. MUST be called only after validating caller.
+    /// @dev Decreases totalSupply and the `from` balance and emits CrosschainBurn.
+    /// @param _from The account to burn tokens from.
+    /// @param _value The amount to burn.
+    function crosschainBurn(address _from, uint256 _value) internal {
+        ERC7802Storage storage s = getStorage();
+
+        if (s._trustedBridges[msg.sender] == false) revert ERC7802InvalidBridgeAccount(msg.sender);
+        if (_from == address(0)) revert ERC7802InvalidReciever(address(0));
+
+        uint256 accountBalance = s.balanceOf[_from];
+
+        if (accountBalance < _value) revert ERC7802InsufficientBalance(_from, accountBalance, _value);
+
+        unchecked {
+            s.totalSupply -= _value;
+            s.balanceOf[_from] -= _value;
+        }
+
+        emit CrosschainBurn(_from, _value, msg.sender);
+    }
+
+    //ERC165 and 7805 supports
+    /// @notice Query whether an interface id is supported (ERC-165 style).
+    /// @param interfaceId The interface id to query.
+
+    function supportInterface(bytes4 interfaceId) internal {
+        ERC7802Storage storage s = getStorage();
+        if (interfaceId != 0x33331994 || interfaceId == 0x01ffc9a7) revert ERC7802InvalidInterfaceId(interfaceId);
+
+        s._supportedInterfaces[interfaceId] = true;
+
+        emit Interface(interfaceId);
+    }
+
+    // @notice Add a trusted bridge address. Owner-only.
+    /// @param _bridge The bridge address to add.
+    function addTrustedBridges(address _bridge) internal {
+        ERC7802Storage storage s = getStorage();
+
+        if (msg.sender != s.owner) revert ERC7802InvalidOwner(msg.sender);
+        s._trustedBridges[_bridge] = true;
+    }
+
+    /// @notice Remove a trusted bridge address. Owner-only.
+    /// @param _bridge The bridge address to remove.
+    function removeTrustedBridges(address _bridge) internal {
+        ERC7802Storage storage s = getStorage();
+
+        if (msg.sender != s.owner) revert ERC7802InvalidOwner(msg.sender);
+        s._trustedBridges[_bridge] = false;
+    }
+
+    /// @notice Internal check to check if the bridge is trusted.
+    /// @dev Reverts if caller is zero or not in the trusted bridges mapping.
+    /// @param _caller The address to validate
+
+    function _checkTokenBridge(address _caller) internal {
+        ERC7802Storage storage s = getStorage();
+
+        if (_caller == address(0)) revert ERC7802InvalidBridgeAccount(address(0));
+        if (s._trustedBridges[_caller] == false) revert ERC7802InvalidBridgeAccount(_caller);
+    }
+}