optimize _beforeTokenTransfer

[code423n4]

Handle

gpersoon

Vulnerability details

Impact

The function _beforeTokenTransfer of RCNftHubL2 can be optimized for gas. This will save the users gas on all future NFT transfers.
See Recommended Mitigation Steps for a suggestion.

Proof of Concept

//https://github.com/code-423n4/2021-08-realitycards/blob/main/contracts/nfthubs/RCNftHubL2.sol#L204
function _beforeTokenTransfer( address from, address to, uint256 tokenId ) internal virtual override(ERC721Enumerable, ERC721) {
super._beforeTokenTransfer(from, to, tokenId);

    if ( msgSender() != address(factory) &&  msgSender() != marketTracker[tokenId] ) {
        IRCMarket market = IRCMarket(marketTracker[tokenId]);
        require(market.state() == IRCMarket.States.WITHDRAW || market.state() == IRCMarket.States.LOCKED, "Incorrect state" );
    }
}

Tools Used

Recommended Mitigation Steps

Use something like the following code:
IRCMarket market = IRCMarket(marketTracker[tokenId]);
if (msgSender() != address(factory) && msgSender() != address(market)) {
IRCMarket.States mstate=market.state();
require(mstate == IRCMarket.States.WITHDRAW || mstate == IRCMarket.States.LOCKED,"Incorrect state");
}
}