add zksync task

basic/07-hardhat/contracts/erc404/ERC404.sol

@@ -0,0 +1,398 @@
+//SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.0;
+
+abstract contract Ownable {
+    event OwnershipTransferred(address indexed user, address indexed newOwner);
+
+    error Unauthorized();
+    error InvalidOwner();
+
+    address public owner;
+
+    modifier onlyOwner() virtual {
+        if (msg.sender != owner) revert Unauthorized();
+
+        _;
+    }
+
+    constructor(address _owner) {
+        if (_owner == address(0)) revert InvalidOwner();
+
+        owner = _owner;
+
+        emit OwnershipTransferred(address(0), _owner);
+    }
+
+    function transferOwnership(address _owner) public virtual onlyOwner {
+        if (_owner == address(0)) revert InvalidOwner();
+
+        owner = _owner;
+
+        emit OwnershipTransferred(msg.sender, _owner);
+    }
+
+    function revokeOwnership() public virtual onlyOwner {
+        owner = address(0);
+
+        emit OwnershipTransferred(msg.sender, address(0));
+    }
+}
+
+abstract contract ERC721Receiver {
+    function onERC721Received(
+        address,
+        address,
+        uint256,
+        bytes calldata
+    ) external virtual returns (bytes4) {
+        return ERC721Receiver.onERC721Received.selector;
+    }
+}
+
+/// @notice ERC404
+///         A gas-efficient, mixed ERC20 / ERC721 implementation
+///         with native liquidity and fractionalization.
+///
+///         This is an experimental standard designed to integrate
+///         with pre-existing ERC20 / ERC721 support as smoothly as
+///         possible.
+///
+/// @dev    In order to support full functionality of ERC20 and ERC721
+///         supply assumptions are made that slightly constraint usage.
+///         Ensure decimals are sufficiently large (standard 18 recommended)
+///         as ids are effectively encoded in the lowest range of amounts.
+///
+///         NFTs are spent on ERC20 functions in a FILO queue, this is by
+///         design.
+///
+abstract contract ERC404 is Ownable {
+    // Events
+    event ERC20Transfer(
+        address indexed from,
+        address indexed to,
+        uint256 amount
+    );
+    event Approval(
+        address indexed owner,
+        address indexed spender,
+        uint256 amount
+    );
+    event Transfer(
+        address indexed from,
+        address indexed to,
+        uint256 indexed id
+    );
+    event ERC721Approval(
+        address indexed owner,
+        address indexed spender,
+        uint256 indexed id
+    );
+    event ApprovalForAll(
+        address indexed owner,
+        address indexed operator,
+        bool approved
+    );
+
+    // Errors
+    error NotFound();
+    error AlreadyExists();
+    error InvalidRecipient();
+    error InvalidSender();
+    error UnsafeRecipient();
+
+    // Metadata
+    /// @dev Token name
+    string public name;
+
+    /// @dev Token symbol
+    string public symbol;
+
+    /// @dev Decimals for fractional representation
+    uint8 public immutable decimals;
+
+    /// @dev Total supply in fractionalized representation
+    uint256 public immutable totalSupply;
+
+    /// @dev Current mint counter, monotonically increasing to ensure accurate ownership
+    uint256 public minted;
+
+    uint256 public ratio;
+
+    // Mappings
+    /// @dev Balance of user in fractional representation
+    mapping(address => uint256) public balanceOf;
+
+    /// @dev Allowance of user in fractional representation
+    mapping(address => mapping(address => uint256)) public allowance;
+
+    /// @dev Approval in native representaion
+    mapping(uint256 => address) public getApproved;
+
+    /// @dev Approval for all in native representation
+    mapping(address => mapping(address => bool)) public isApprovedForAll;
+
+    /// @dev Owner of id in native representation
+    mapping(uint256 => address) internal _ownerOf;
+
+    /// @dev Array of owned ids in native representation
+    mapping(address => uint256[]) internal _owned;
+
+    /// @dev Tracks indices for the _owned mapping
+    mapping(uint256 => uint256) internal _ownedIndex;
+
+    /// @dev Addresses whitelisted from minting / burning for gas savings (pairs, routers, etc)
+    mapping(address => bool) public whitelist;
+
+    // Constructor
+    constructor(
+        string memory _name,
+        string memory _symbol,
+        uint8 _decimals,
+        uint256 _totalNativeSupply,
+        address _owner,
+        uint256 _ratio
+    ) Ownable(_owner) {
+        name = _name;
+        symbol = _symbol;
+        decimals = _decimals;
+        ratio = _ratio;
+        totalSupply = _totalNativeSupply * (10 ** (decimals+_ratio));
+    }
+
+    /// @notice Initialization function to set pairs / etc
+    ///         saving gas by avoiding mint / burn on unnecessary targets
+    function setWhitelist(address target, bool state) public onlyOwner {
+        whitelist[target] = state;
+    }
+
+    /// @notice Function to find owner of a given native token
+    function ownerOf(uint256 id) public view virtual returns (address owner) {
+        owner = _ownerOf[id];
+
+        if (owner == address(0)) {
+            revert NotFound();
+        }
+    }
+
+    /// @notice tokenURI must be implemented by child contract
+    function tokenURI(uint256 id) public view virtual returns (string memory);
+
+    /// @notice Function for token approvals
+    /// @dev This function assumes id / native if amount less than or equal to current max id
+    function approve(
+        address spender,
+        uint256 amountOrId
+    ) public virtual returns (bool) {
+        if (amountOrId <= minted && amountOrId > 0) {
+            address owner = _ownerOf[amountOrId];
+
+            if (msg.sender != owner && !isApprovedForAll[owner][msg.sender]) {
+                revert Unauthorized();
+            }
+
+            getApproved[amountOrId] = spender;
+
+            emit Approval(owner, spender, amountOrId);
+        } else {
+            allowance[msg.sender][spender] = amountOrId;
+
+            emit Approval(msg.sender, spender, amountOrId);
+        }
+
+        return true;
+    }
+
+    /// @notice Function native approvals
+    function setApprovalForAll(address operator, bool approved) public virtual {
+        isApprovedForAll[msg.sender][operator] = approved;
+
+        emit ApprovalForAll(msg.sender, operator, approved);
+    }
+
+    /// @notice Function for mixed transfers
+    /// @dev This function assumes id / native if amount less than or equal to current max id
+    function transferFrom(
+        address from,
+        address to,
+        uint256 amountOrId
+    ) public virtual {
+        if (amountOrId <= minted) {
+            if (from != _ownerOf[amountOrId]) {
+                revert InvalidSender();
+            }
+
+            if (to == address(0)) {
+                revert InvalidRecipient();
+            }
+
+            if (
+                msg.sender != from &&
+                !isApprovedForAll[from][msg.sender] &&
+                msg.sender != getApproved[amountOrId]
+            ) {
+                revert Unauthorized();
+            }
+
+            balanceOf[from] -= _getUnit();
+
+            unchecked {
+                balanceOf[to] += _getUnit();
+            }
+
+            _ownerOf[amountOrId] = to;
+            delete getApproved[amountOrId];
+
+            // update _owned for sender
+            uint256 updatedId = _owned[from][_owned[from].length - 1];
+            _owned[from][_ownedIndex[amountOrId]] = updatedId;
+            // pop
+            _owned[from].pop();
+            // update index for the moved id
+            _ownedIndex[updatedId] = _ownedIndex[amountOrId];
+            // push token to to owned
+            _owned[to].push(amountOrId);
+            // update index for to owned
+            _ownedIndex[amountOrId] = _owned[to].length - 1;
+
+            emit Transfer(from, to, amountOrId);
+            emit ERC20Transfer(from, to, _getUnit());
+        } else {
+            uint256 allowed = allowance[from][msg.sender];
+
+            if (allowed != type(uint256).max)
+                allowance[from][msg.sender] = allowed - amountOrId;
+
+            _transfer(from, to, amountOrId);
+        }
+    }
+
+    /// @notice Function for fractional transfers
+    function transfer(
+        address to,
+        uint256 amount
+    ) public virtual returns (bool) {
+        return _transfer(msg.sender, to, amount);
+    }
+
+    /// @notice Function for native transfers with contract support
+    function safeTransferFrom(
+        address from,
+        address to,
+        uint256 id
+    ) public virtual {
+        transferFrom(from, to, id);
+
+        if (
+            to.code.length != 0 &&
+            ERC721Receiver(to).onERC721Received(msg.sender, from, id, "") !=
+            ERC721Receiver.onERC721Received.selector
+        ) {
+            revert UnsafeRecipient();
+        }
+    }
+
+    /// @notice Function for native transfers with contract support and callback data
+    function safeTransferFrom(
+        address from,
+        address to,
+        uint256 id,
+        bytes calldata data
+    ) public virtual {
+        transferFrom(from, to, id);
+
+        if (
+            to.code.length != 0 &&
+            ERC721Receiver(to).onERC721Received(msg.sender, from, id, data) !=
+            ERC721Receiver.onERC721Received.selector
+        ) {
+            revert UnsafeRecipient();
+        }
+    }
+
+    /// @notice Internal function for fractional transfers
+    function _transfer(
+        address from,
+        address to,
+        uint256 amount
+    ) internal returns (bool) {
+        uint256 unit = _getUnit();
+        uint256 balanceBeforeSender = balanceOf[from];
+        uint256 balanceBeforeReceiver = balanceOf[to];
+
+        balanceOf[from] -= amount;
+
+        unchecked {
+            balanceOf[to] += amount;
+        }
+
+        // Skip burn for certain addresses to save gas
+        if (!whitelist[from]) {
+            uint256 tokens_to_burn = (balanceBeforeSender / unit) -
+                (balanceOf[from] / unit);
+            for (uint256 i = 0; i < tokens_to_burn; i++) {
+                _burn(from);
+            }
+        }
+
+        // Skip minting for certain addresses to save gas
+        if (!whitelist[to]) {
+            uint256 tokens_to_mint = (balanceOf[to] / unit) -
+                (balanceBeforeReceiver / unit);
+            for (uint256 i = 0; i < tokens_to_mint; i++) {
+                _mint(to);
+            }
+        }
+
+        emit ERC20Transfer(from, to, amount);
+        return true;
+    }
+
+    // Internal utility logic
+    function _getUnit() internal view returns (uint256) {
+        return 10 ** (decimals + ratio);
+    }
+
+    function _mint(address to) internal virtual {
+        if (to == address(0)) {
+            revert InvalidRecipient();
+        }
+
+        unchecked {
+            minted++;
+        }
+
+        uint256 id = minted;
+
+        if (_ownerOf[id] != address(0)) {
+            revert AlreadyExists();
+        }
+
+        _ownerOf[id] = to;
+        _owned[to].push(id);
+        _ownedIndex[id] = _owned[to].length - 1;
+
+        emit Transfer(address(0), to, id);
+    }
+
+    function _burn(address from) internal virtual {
+        if (from == address(0)) {
+            revert InvalidSender();
+        }
+
+        uint256 id = _owned[from][_owned[from].length - 1];
+        _owned[from].pop();
+        delete _ownedIndex[id];
+        delete _ownerOf[id];
+        delete getApproved[id];
+
+        emit Transfer(from, address(0), id);
+    }
+
+    function _setNameSymbol(
+        string memory _name,
+        string memory _symbol
+    ) internal {
+        name = _name;
+        symbol = _symbol;
+    }
+}